detection of multiplets and application to turkey-Syria seismic crisis of february 2023
The correlation technique, or template matching, applied to the detection and analysis of seismic events has demonstrated its performance and usefulness in the processing chain of the CEA/DAM National Data Center. Unfortunately, this method suffers from limitations which limit its effectiveness and its use in the operational environment, linked on the one hand to the computational cost of massive data processing, and on the other hand to the rate of false detections that could generate low-level processing. The use of denoising methods upstream of processing (example: deepDenoiser, by Zhu et al., 2020), could also increase the number of erroneous detections. The first part of the research project consists of providing a methodology aimed at improving the processing time performance of the multiplets detector, in particular by using information indexing techniques developed in collaboration with LIPADE (L-MESSI method , Botao Peng, Panagiota Fatourou, Themis Palpanas. Fast Data Series Indexing for In-Memory Data. International Journal on Very Large Data Bases (VLDBJ) 2021). The second part of the project concerns the development of an auto-encoder type “filtering” tool for false detections built using machine learning. The Syria-Turkey seismic crisis of February 2023, dominated by two earthquakes of magnitude greater than 7.0, will serve as a learning database for this study.
Formulation of organic electrode materials for Li-ion batteries with low environmental impact
This project delas with the development of Li-ion battery prototype with a capacity of 500mAh only based on the use of organic elecrode materials (PTCLi4 for the negative electrode and MgLi2pDHT for the positive electrode) combined with a polymer electrolyte developped by CNRS/LEPMI. It will focus on the issues related to material implementation in order to prepare électrodes containing low carbon ration (2mAh/cm2)
Polymeric reversible conductive adhesive for recyclable electronics
Electronic devices contain valuable and noxious metals that are today hardly recovered. While the demand for electronics is still growing, the urge for recyclable electronics development grows stronger. Printed Circuit Boards (PCB) are the core of electronics and contain electronic component that are fixed onto metal tracks through conductive adhesives. Such adhesives contain generally a metallic filler and a polymeric binder that is generally a polymerizable thermoset formulation.
With the increasing topics on material circularity, self-immolative polymers (SIP), polymer systems that have the ability to undergo depolymerization with a stimulus, have emerged in the recent years as viable systems to bring recyclability to polymer materials.
The current post-doc will develop a polymerizable SIP binder to be used in conductive adhesive in PCB applications. After the selection of adequate chemistries, the post-doc will synthesize SIP and evaluate their thermal and mechanical properties and their ability to depolymerize under stimulus. In a second step, the most promising SIP will be formulated as a conductive adhesive and will be applied to a PCB. The recyclability of the final object will be studied.
Development of piezoelectric resonators for power conversion
CEA-Leti has been working to improve energy conversion technologies for over 10 years. Our research focuses on designing more efficient and compact converters by leveraging GaN-based transistors, thereby setting new standards in terms of ultra-fast switching and energy loss reduction.
In the pursuit of continuous innovation, we are exploring innovative paths, including the integration of piezoelectric mechanical resonators. These emerging devices, capable of storing energy in the form of mechanical deformations, offer a promising perspective for increased energy density, particularly at high frequencies (>1 MHz). However, the presence of parasitic resonance modes impacts the overall efficiency of the system. Therefore, we are in need of an individual with skills in mechanics, especially in vibrational mechanics, to enhance these cleanroom-manufactured micromechanical resonators.
You will be welcomed in Grenoble within a team of engineers, researchers and doctoral students, dedicated to innovation for energy, which combines the skills of microelectronics and power systems from two CEA institutes, LETI and LITEN, close to the needs of the industry (http://www.leti-cea.fr/cea-tech/leti/Pages/recherche-appliquee/plateformes/electronique-puissance.aspx).
If you are a scientifically inclined mind, eager to tackle complex challenges, passionate about seeking innovative solutions, and ready to contribute at the forefront of technology, this position/project represents a unique opportunity. Join our team to help us push the boundaries of energy conversion.
References : http://scholar.google.fr/citations?hl=fr&user=s3xrrcgAAAAJ&view_op=list_works&sortby=pubdate
Modeling of charge noise in spin qubits
Thanks to strong partnerships between several research institutes, Grenoble is a pioneer in the development of future technologies based on spin qubits using manufacturing processes identical to those used in the silicon microelectronics industry. The spin of a qubit is often manipulated with alternating electrical (AC) signals through various spin-orbit coupling (SOC) mechanisms that couple it to electric fields. This also makes it sensitive to fluctuations in the qubit's electrical environment, which can lead to large qubit-to-qubit variability and charge noise. The charge noise in the spin qubit devices potentially comes from charging/discharging events within amorphous and defective materials (SiO2, Si3N4, etc.) and device interfaces. The objective of this postdoc is to improve the understanding of charge noise in spin qubit devices through simulations at different scales. This research work will be carried out using an ab initio type method and also through the use of the TB_Sim code, developed within the CEA-IRIG institute. This last one is able of describing very realistic qubit structures using strong atomic and multi-band k.p binding models.
Development, metrological validation and outdoor testing of a multitrack Raman/FO measurement unit dedicated to the safety of future cryogenic liquid hydrogen dispensing stations
Context: The domestic and industrial use of liquid hydrogen as the fuel of the future requires the definition of a suitable safety code. At present, tank separation criteria have been defined by anticipation using a conservative approach. It is therefore necessary to carry out full-scale experiments ("pool spreading") in order to provide input for calculation codes and build relevant standards. These experiments require the implementation of instrumentation adapted to the measurement of all gases present in free space (O2, N2, H2O, H2) in order to establish a measurement of partial pressures during each test, correlated with the other means of measurement in place (thermometry, catharometry, PIV, BOS, etc.).
Mission: In the context of an ANR-PEPR project (ESKHYMO) managed by CEA Liten, a Raman/FO Multitrack spectrometric measurement unit will be developed jointly by CEA List and CEA DES on the basis of an existing device. Raman measurement is multi-elemental, multi-track (a single measurement unit for several probes), non-explosive, and delivers a self-standardized measurement to a reference species (usually nitrogen at atmospheric pressure). The Raman/FO measurement unit comprises a laser, a spectrometer associated with a scientific CCD camera, and a fiber-optic circuit for remote measurement. The design of the Raman/FO probes will also be based on an existing CEA product, which will be miniaturized for deployment in field conditions. Four Raman/FO probes will be produced and then calibrated in air (climatic chamber) and hydrogen (shock tube or vacuum chamber) at CEA DES DM2S in Saclay. Finally, the final device will be deployed on the test site for multi-gas measurements during spraying experiments, in partnership with Air Liquide and accrediting bodies (INERIS).
Skills: Optics, laser, fiber optics, spectrometry
Post-Doc - Research Engineer In-situ characterization coupled with electro-reduction of CO2
This project concerns the Circular Carbon Economy program. It proposes mature solutions for industrial decarbonization based on electrochemical CO2 recovery. The candidate will be in charge of developing an electrolyzer for optimized conversion of CO2 into CO; a key molecule in the synthesis of many carbon-based products; by integrating in-situ characterization resources (UV-Vis, Infra-Red). The development of customized cells coupled with this local characterization, should enable to gain a better understanding of reaction phenomena, determine the diffusion mechanisms of species in the electrolytic medium, and extend the analysis to the entire electrochemical system. Studies and experiments will allow to optimize not only the catalytic system, but also the various cell components (membrane, electrode, Gas Diffusion Layer / Gas Diffusion Electrode, electrolyte, CO2 routing), in order to propose innovative, high-performance electrolyzer designs.
Design and fabrication of magnetic cores having permeability gradient using additive manufacturing
As a major technological research institute, the CEA-Liten plays a decisive role in the development of future technologies for the energy transition and the limitation of greenhouse gas emissions. The laboratory develops magnetic components working at high frequency (> 100 kHz) for an integration in compact power electronics converters. Today, the discrete magnetic components are among the most bulky parts in the power converters (~30-40%) and they are responsible of almost 40-50% of the heat losses. The advent of wide band gap semiconductors (SiC or GaN) increases the switching frequency to values above 100 kHz. This strategy helps to reduce, theoretically, the dimensions of the passives but the thermal constraints (due to the losses produced at a higher frequency) and the electromagnetic compatibility (EMC; due to the noise emerging from faster switching commutations) may constitute an issue (in a system approach). In this sense, the developments of new architectures (based on advanced core geometries or clever magnetic materials arrangements) may constitute a breakthrough. The diversity of present cores and fabrication technologies permit small incremental gains on these magnetic components integrations. Additive manufacturing is a very emerging fabrication process that allow not only developing new core geometry but also, the adjustment of core composition (by allowing the deposition of layers containing different ferrite powder composition). The post-doctoral fellow will work on the design of a core having a permeability gradient and on its electrical and thermal characterizations. The post-doctoral fellowship is of 2 years duration located in the city of Grenoble (France) with a minimum wage of 40 k€ per year. If you want to have more detail please use the following link: https://liten.cea.fr/cea-tech/liten/Documents/Postdoc-Carnot-EF/AMbassador.pdf
Manufacturing of analytical microsystems by thermoplastics micro-milling
Micro-fabrication techniques and especially micro-milling can be used to manufacture microsystem prototypes with a timescale of days, as close as possible to the application. Polymethylmethacrylate (PMMA - Commercial name Plexiglas) is a commonly used material for microsystems fabrication, limited however by its chemical incompatibility with acids and solvents.
The goal of this post-doctoral project is to study the feasibility of machining thermoplastic materials other than PMMA and to optimise the associated manufacturing parameters. The post-doctoral project will start with the selection of materials in line with the aimed applications (optical and physico-chemical properties). The materials will be selected among the thermoplastics family (PC, POM, PS, HDPE, PEEK, PVC, PP, PTFE, ULTEM, etc).
The optimisation of the micro-milling step will be realized by varying parameters such as the tool rotation speed, the feed rates, the depth of cut, etc. The surfaces and channels will be characterized by optical or mechanical profilometry, optical microscopy and/or scanning electron microscopy.