French National Centre for Scientific Research

A refurbished metal-as-insulation (MI) HTS insert comprised of DP coils with replaced inner joints was charged under various magnetic field ( B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ext</sub> ) from 0 to 18 T at 4.2 K for testing. However, the refurbished insert could not be charged up to its maximum field, because the cryogenic condition tended to be unstable with a high helium boiling rate above 28 T. Therefore, to investigate the cooling issue, four Cernox sensors were installed in refurbished insert. The temperature of each position while powering the insert was measured under various B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ext</sub> . In addition, we qualified a new simplified protection scheme without the usual detection and dump circuit during a quench at B <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ext</sub> = 9 T of the insert. Detailed experimental results about charging and quenching tests of the insert are presented and discussed in this paper.

To accompany the development of High Temperature Superconductor (HTS) magnets at the Laboratoire National des Champs Magnétiques Intenses, we have initiated an activity on implementing numerical models to simulate HTS with the Feel++ finite element (FE) library used for the simulation of the lab high field resistive magnets. In this work, we give an overview of the status of the implementations. We focus on the modeling of the Nougat HTS – that reached 32.5 Tesla in a resistive magnet background field of 18 Tesla. We present some simulations run in parallel that we carried out: for the current density redistribution in the HTS based on the T-A formulation and for the estimation of the critical current as a function of the external applied magnetic field using an iterative algorithm based on A formulation. The results were validated using comparison with experiments and numerical estimations from [1].

The generation of non-destructive pulsed magnetic fields of 100 T involves high mechanical stress, due to the Lorentz forces, sustainable by few conductors. At LNCMI, in the inner coil (the most mechanically stressed) of the 100 T triple coil system a Cu-Nb commercial conductor is used. This work explains firstly how a new bi-material design of the inner coil allows to reduce the quantity of the Cu-Nb wire used. Secondly, in order to replace this commercial Cu-Nb wire, the way to increase the volume of Ag-Cu composite conductors produced at CIRIMAT and LNCMI by powder metallurgy, Spark Plasma Sintering and wire drawing at room temperature is discussed.

Planar transformer technology provides a serious alternative to wound transformers for improving the efficiency and power density of isolated converters. The flat shape of its coil turns and the interleaving of its windings allow an excellent control of the skin and proximity effects. The major drawback of planar technology is the strong capacitive couplings between the windings. These couplings are detrimental to the increased switching frequency induced by the new wide-bandgap transistors, and to electromagnetic compatibility. Using fundamental equations, material properties and geometric dimensions, the present work proposes a semi-analytical electromagnetic model of planar transformers able to account for capacitive couplings. Compared with current models, it allows rapid estimation of all its sizing parameters : losses, leakage inductance, bandwidth and interwinding impedance. This novel model was experimentally validated over a wide frequency range (1 kHz up to 100 MHz) using transformers with both series and parallel connected windings.

This work presents a simple power converter, without any high voltage transformer, able to supply and control a plasma jet based on dielectric barrier discharge. The converter, operating in pulsed current mode, requires a single power switch and is fed by a low voltage DC source. It can deliver very short duration pulses to the plasma jet with high current amplitude. The operating principle is explained by means of the state plane analysis and is validated with simulations and experimental results. The equations provided allow for the calculation during the design stage of important characteristics of the plasma jet as the peak voltage and the duration of the pulses. The power can be easily adjusted during experimentation to comply with the desired appearance of the plasma jet.

As part of the development of many robotic systems for the forestry sector, forest scene understanding requires the use of computer vision algorithms. However, this dense and unstructured environment is complex and puts conventional detection approaches to the test. In the case of tree instance segmentation, the presence of closely spaced or even intertwined trees, their highly variable shapes, and complex masks due to their branches and leaves are just some of the challenges to be overcome. For this, specific learning of tree boundaries is required to better distinguish one from another. In this paper, we propose ConvexMask, a convolutional neural network for real-time instance segmentation. ConvexMask opts for a label representation approach with a convex exterior polygon, defined by tree extremities, and a binary mask to handle the detail and occlusions that the label may contain. Experiments conducted on the SynthTree43k dataset show that ConvexMask distinguishes tree extremities better than state-of-the-art networks, resulting in better-quality masks. The code is available at https://github.com/rcondat/convexmask</uri

Robotic assistance can improve the learning of complex motor skills. However, the assistance designed and used up to now mainly guides motor commands for trajectory learning, not dynamics learning. The present study explored how a complex motor skill involving the right arm can be learned without suppressing task dynamics, by means of an innovative device with robotic guidance that allows a torque versus motion profile to be learned with admittance control. In addition, we assessed how concurrent visual feedback on this profile can enhance learning without creating dependency, by means of a fading procedure (i.e., feedback reduction across trials). On Day 1, a Control group performed an acquisition session (6 blocks) featuring concurrent visual feedback, while a Fading group performed the session with a gradual reduction in feedback (from 100% to 0% over the 6 blocks). On Day 2, both groups performed a block first without feedback (i.e., Transfer test), then with feedback (i.e., Retention test). Results revealed that on Day 1, movement rehearsal induced a significant improvement in spatiotemporal parameters for the Control group, compared with the Fading group. On Day 2, the opposite was found when this visual feedback was removed, as the Fading group performed significantly better than the Control group on the Transfer test. Vision allows a relationship to be established between the required torque and the motion profile. Its suppression then forces the processing of more intrinsic information , leading to the development of a stable internal representation of the task.

Many humanoid and multi-legged robots are controlled in positions rather than in torques, which prevents direct control of contact forces, and hampers their ability to create multiple contacts to enhance their balance, such as placing a hand on a wall or a handrail. This paper introduces the SEIKO (Sequential Equilibrium Inverse Kinematic Optimization) pipeline, and proposes a unified formulation that exploits an explicit model of flexibility to indirectly control contact forces on traditional position-controlled robots. SEIKO formulates whole-body retargeting from Cartesian commands and admittance control using two quadratic programs solved in real time. Our pipeline is validated with experiments on the real, full-scale humanoid robot Talos in various multi-contact scenarios, including pushing tasks, far-reaching tasks, stair climbing, and stepping on sloped surfaces. Code and videos are available at: https://hucebot.github.io/seiko_controller_website/</uri

G‐quadruplex DNA structures (G4) are proven to interfere with most genetic and epigenetic processes. Small molecules binding these structures (G4 ligands) are invaluable tools to probe G4‐biology and address G4‐druggability in various diseases (cancer, viral infections). However, the large number of reported G4 ligands (>1000) could lead to confusion while selecting one for a given application. Herein we conducted a systematic affinity ranking of 11 popular G4 ligands vs 5 classical G4 sequences using FRET‐melting, G4‐FID assays and SPR. Interestingly SPR data globally align with the rankings obtained from the two semi‐quantitative assays despite discrepancies due to limits and characteristics of each assay. In the whole, PhenDC3 emerges as the most potent binder irrespective of the G4 sequence. Immediately below PDS, PDC‐360A, BRACO19, TMPyP4 and RHPS4 feature strong to medium binding again with poor G4 topology discrimination. More strikingly, the G4 drugs Quarfloxin, CX5461 and c‐PDS exhibit weak affinity with all G4s studied. Finally, NMM and Cu‐ttpy showed heterogeneous behaviors due, in part, to their physicochemical particularities poorly compatible with screening conditions. The remarkable properties of PhenDC3 led us to propose its use for benchmarking FRET‐melting and G4‐FID assays for rapid G4‐affinity evaluation of newly developed ligands.

Nickel‐catalyzed intramolecular hydrosilylation can be efficiently achieved with high regio‐ and stereoselectivities through two distinct methodologies. The first approach utilizes a conventional method, involving the reduction of nickel salt (NiBr2‐2,2’‐bipyridine) using manganese metal. The second method employs a one‐step electrochemical reaction, utilizing the sacrificial anode process and NiBr2bipy catalysis. Both methods yield silylated heterocycles in good to high yields through a syn‐exo‐dig cyclization process. Control experiments and molecular electrochemistry (cyclic voltammetry) provided further insights into the reaction mechanism.

The μLAS technology enables in-line DNA concentration and separation in a microchannel. Here, we describe its operation to analyze the size profile of cell-free DNA (cfDNA) extracted from blood plasma. Operated on commercial systems for capillary electrophoresis, we provide the size distribution of healthy individuals or patients using an input of 10 μL.

Protein secretion is a key cellular functionality, particularly in immunology, where cells can display large heterogeneity in this crucial activity in addition to binary secretion behavior. However, few methods enable quantitative secretion rate measurements at the single-cell level, and these methods are mostly based on microfluidics systems. Here, we describe such a microfluidic single-cell method for precisely measuring protein secretion rates in detail, building on the published droplet-based microfluidic platform DropMap. We give an updated, detailed guide toward quantifying protein secretion rates, discussing its setup and limitations. We illustrate the protocol on two key immunological analytes, immunoglobulin G, and interferon-γ.

The encounter between the Jovian co‐rotating plasma and Ganymede gives rise to electromagnetic waves that propagate along the magnetic field lines and accelerate particles by resonant or non‐resonant wave‐particle interaction. They ultimately precipitate into Jupiter's atmosphere and trigger auroral emissions. In this study, we use Juno/JADE, Juno/UVS data, and magnetic field line tracing to characterize the properties of electrons accelerated by the Ganymede‐magnetosphere interaction in the far‐field region. We show that the precipitating energy flux exhibits an exponential decay as a function of downtail distance from the moon, with an e‐folding value of 29°, consistent with previous UV observations from the Hubble Space Telescope (HST). We characterize the electron energy distributions and show that two distributions exist. Electrons creating the Main Alfvén Wing (MAW) spot and the auroral tail always have broadband distribution and a mean characteristic energy of 2.2 keV while in the region connected to the Transhemispheric Electron Beam (TEB) spot the electrons are distributed non‐monotonically, with a higher characteristic energy above 10 keV. Based on the observation of bidirectional electron beams, we suggest that Juno was located within the acceleration region during the 11 observations reported. We thus estimate that the acceleration region is extended, at least, between an altitude of 0.5 and 1.3 Jupiter radius above the 1‐bar surface. Finally, we estimate the size of the interaction region in the Ganymede orbital plane using far‐field measurements. These observations provide important insights for the study of particle acceleration processes involved in moon‐magnetosphere interactions.

Crops generally have seeds larger than their wild progenitors´ and with reduced dormancy. In wild plants, seed mass and allocation to the seed coat (a proxy for physical dormancy) scale allometrically so that larger seeds tend to allocate less to the coats. Larger seeds and lightweight coats might thus have evolved as correlated traits in crops. We tested whether 34 crops and 22 of their wild progenitors fit the allometry described in the literature, which would indicate co‐selection of both traits during crop evolution. Deviations from the allometry would suggest that other evolutionary processes contribute to explain the emergence of larger, lightweight‐coated seeds in crops. Crops fitted the scaling slope but deviated from its intercept in a consistent way: Seed coats of crops were lighter than expected by their seed size. The wild progenitors of crops displayed the same trend, indicating that deviations cannot be solely attributed to artificial selection during or after domestication. The evolution of seeds with small coats in crops likely resulted from a combination of various pressures, including the selection of wild progenitors with coats smaller than other wild plants, further decreases during early evolution under cultivation, and indirect selection due to the seed coat‐seed size allometry.

Efficient semi‐transparent solar cells can extend the adoption of photovoltaics beyond standard utility‐scale, commercial, or residential applications. Halide perovskites are particularly suitable in this respect owing to their tunable bandgap. The main drawbacks in the development of transparent perovskite solar cells are the high open‐circuit voltage (Voc) deficit and the difficulties in depositing high‐quality thin films over large area substrates, given the low solubility of bromide and chloride precursors. In this work, passivation strategies are developed for the high bandgap Br perovskite able to reduce charge recombination and consequently improve the Voc. The study demonstrates 1 cm² perovskite solar cells with Voc up to 1.73 V (1.83 eV Quasi Fermi Level Splitting) and a PCE of 8.1%. The average visible transmittance (AVT) exceeds 70% by means of a bifacial light management and a record light utilization efficiency (LUE) of 5.72 is achieved. Moreover, the potential use of the technology is evaluated toward Internet of Things (IoT) application owing to a bifaciality factor of 87% along with 17% PCE under indoor lighting. Finally, the up‐scaling is demonstrated by fabricating 20 cm² active area modules with PCE of 7.3% and Voc per cell up to 1.65 V.

We present a computationally efficient algorithm that is suitable for graphic processing unit implementation. This algorithm enables the identification of all weak pseudo-manifolds that meet specific facet conditions, drawn from a given input set. We employ this approach to enumerate toric colorable seeds. Consequently, we achieve a comprehensive characterization of ( n − 1 ) (n-1) -dimensional PL spheres with n + 4 n+4 vertices that possess a maximal Buchstaber number. A primary focus of this research is the fundamental categorization of non-singular complete toric varieties of Picard number 4. This classification serves as a valuable tool for addressing questions related to toric manifolds of Picard number 4. Notably, we have determined which of these manifolds satisfy equality within an inequality regarding the number of minimal components in their rational curve space. This addresses a question posed by Chen, Fu, and Hwang in 2014 for this specific case.

Amphibians globally suffer from emerging infectious diseases like chytridiomycosis caused by the continuously spreading chytrid fungi. One is Batrachochytrium salamandrivorans (Bsal) and its disease ‒ the ‘salamander plague’ ‒ which is lethal to several caudate taxa. Recently introduced into Western Europe, long distance dispersal of Bsal, likely through human mediation, has been reported. Herein we study if Alpine salamanders (Salamandra atra and S. lanzai) are yet affected by the salamander plague in the wild. Members of the genus Salamandra are highly susceptible to Bsal leading to the lethal disease. Moreover, ecological modelling has shown that the Alps and Dinarides, where Alpine salamanders occur, are generally suitable for Bsal. We analysed skin swabs of 818 individuals of Alpine salamanders and syntopic amphibians at 40 sites between 2017 to 2022. Further, we compiled those with published data from 319 individuals from 13 sites concluding that Bsal infections were not detected. Our results suggest that the salamander plague so far is absent from the geographic ranges of Alpine salamanders. That means that there is still a chance to timely implement surveillance strategies. Among others, we recommend prevention measures, citizen science approaches, and ex situ conservation breeding of endemic salamandrid lineages.

Flavins and their alloxazine isomers are key chemical scaffolds for bioinspired electron transfer strategies. Their properties can be fine‐tuned by functional groups, which must be introduced at an early stage of the synthesis as their aromatic ring is inert towards post‐functionalization. We show that the introduction of a remote metal‐binding redox site on alloxazine and flavin activates their aromatic ring towards direct C−H functionalization. Mechanistic studies are consistent with a synthetic sequence involving ground‐state single electron transfer (SET) with an electrophilic source followed by radical‐radical coupling. This unprecedented reactivity opens new opportunities in molecular editing of flavins by direct aromatic post‐functionalization and the utility of the method is demonstrated with the site‐selective C6 functionalization of alloxazine and flavin with a CF3 group, Br or Cl, that can be further elaborated into OH and aryl for chemical diversification.