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High-Pressure High-Temperature Nanodiamond-Modified ZnO Nanocomposites as Promising Photocatalysts: Synthesis and Characterization
No full textInternational audienceZinc oxide (ZnO) nanostructures suffer from fast electron–hole recombination, limiting their applicability in photocatalytic environmental remediation, and carbon additives such as detonation nanodiamonds (DNDs) are constrained by their high defect density. To address this, ZnO nanocomposites modified with high-pressure, high-temperature nanodiamonds (HPHT NDs) were synthesized to evaluate whether their intrinsically lower defect density—evidenced by a dominant diamond Raman peak at 1330 cm−1 and a low sp2 carbon fraction of 6.6% compared to oxidized DNDs with strong D/G bands (~1350/1580 cm−1) and ~25–35% sp2 carbon—can enhance charge separation and improve photocatalytic activity. Oxidized HPHT NDs bearing carbonyl, carboxyl, and hydroxyl groups enabled covalent attachment to ZnO, and the resulting ND–ZnO composites were characterized by SEM/EDX, ATR-FTIR, Raman spectroscopy, XPS, and cathodoluminescence (CL). EDX confirmed increasing carbon incorporation from 13.0 to 52.9 at.%, while XPS revealed a 0.5 eV shift in the Zn 2p3/2 peak and an increase in Zn–O–Zn lattice oxygen from 31.3% to 61.6% in ND–ZnO 10. CL showed enhanced near-band-edge emission and reduced Zni-related luminescence (~3.0 eV). ND–ZnO 10 achieved a nearly threefold-higher degradation rate constant (0.0251 min−1) than pristine ZnO (0.0087 min−1) and retained 88% efficiency after five cycles, demonstrating strong potential for durable wastewater treatmen
Tunable polarization-entangled near-infrared photons from orthogonal GaAs nanowires
No full textQuantum entanglement is a fundamental resource for emerging quantum technologies, enabling secure communication and enhanced sensing. For decades, generating polarization entangled states has been mainly achieved using bulk crystals with spontaneous parametric down conversion (SPDC), preventing scalability and on chip integration. Miniaturizing the quantum source provides access to more versatility and tunability while enabling an easier integration to other devices, notably necessary for satellite-based quantum communication, and eventually reducing fabrication costs. This challenging task can be achieved with Zinc Blende GaAs nanowires. They already have shown an efficient photon pairs generation via SPDC at 1550 nm. Here we demonstrate that a pair of orthogonal GaAs nanowires constitutes a new nanoscale platform to control the quantum state at telecommunication wavelength, enabling a transition from polarization entangled to separable states as a function of the pump polarization, with fidelities reaching 90
ON THE FILTERED SPECTRAL ABSCISSA FOR DELAY-DIFFERENCE EQUATIONS AND ITS ROLE IN THE BOUNDARY CONTROL OF HYPERBOLIC PDES
No full textFeedback control systems governed by delay-differential equations of neutral type may be fragile, in the sense that arbitrarily small parametric perturbations and implementation errors of the control may destroy the exponential stability of the target closed-loop system. Such instability problems can be resolved by including a low-pass filter in the control loop, on the condition that the filter itself is not destabilizing. The analysis of this condition for delay-difference equations has recently led to the notion of filtered spectral abscissa. In this paper, we first analyze the filtered spectral abscissa, where we remove the stringent condition of commensurate delays previously made, and we derive novel mathematical and computationally tractable characterizations. Second, we highlight the role of the filtered spectral abscissa in the context of boundary control of first-order hyperbolic partial differential equations, grounded in integral transformations that result in delaydifference equation models with both discrete and distributed delays. In particular, we show that in the situation where reflection terms cannot be robustly canceled out by the control -that is, their direct cancellation would lead to a fragile closed-loop system -a negative filtered spectral abscissa of the delay-difference equation, obtained by removing the distributed delay terms, is the necessary and sufficient condition -in addition to the exponential stability of the target closed-loop system -for the safe inclusion of a filter with sufficiently high cut-off
De nouveaux alliés du bien-être des animaux confrontés aux défis des transitions agroécologiques et climatiques
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End-To-End Multi-View Multi-Modal Detection-Driven Image Fusion: One Method to Fuse them all
No full textWe present EDIF, an end-to-end detection-driven framework designed to unify multi-modal and multi-view image fusion within a single architecture. While most existing fusion methods address either spectral complementarity (multi-modal) or viewpoint variability (multi-view) in isolation, real-world perception systems increasingly require both. EDIF formulates fusion as an object-level alignment problem: heterogeneous images are encoded as sets of keypoints, which are matched and aggregated through a graph attention mechanism to form object-centric representations directly optimized for detection. To stabilize training across heterogeneous components, we introduce a three-stage task-driven strategy that progressively aligns keypoint extraction, object localization, and cross-sensor grouping. In addition, we release the Multi-Modal and Multi-View Object Detection Dataset (MMDOD), a new benchmark designed to study detection-driven fusion under strong modality–view dependencies. MMDOD contains over 10,000 images of transparent objects captured under four complementary modalities (visible, NIR, low-contrast, polarization shift) and six viewpoints, with detailed object-level annotations. Experiments on RGB–thermal, multi-camera, and joint multi-modal multi-view benchmarks show that EDIF achieves performance competitive with recent specialized methods, while uniquely operating within a unified framework. On MMDOD, EDIF significantly outperforms adapted multi-modal multi-view baselines, highlighting the benefits of detection-driven, object-level fusion. The proposed MMDOD dataset is publicly available at https://datasets.liris.cnrs.fr/mmdod-version1
Towards absolute measurements of magnetic losses by the rotational single sheet tester (RSST): an interlaboratory comparison
No full textInternational audienceA comparison of the magnetic energy loss measurement in non-oriented Fe-Si sheets under alternating and rotational polarization has been accomplished by four European laboratories using different Rotational Single-Sheet Tester (RSST) setups and different sample shapes. The measurements, performed in the frequency and polarization intervals 5 Hz ≤ f ≤ 200 Hz, 1.0 T ≤ J p ≤ 1.5 T, aimed at providing a benchmark test for these special measurements, looking for a connection between the RSST outcomes and absolute loss values, obtained by a combination of IEC 60404-2 Epstein data and precise local measurements. The laboratory-averaged RSST alternating loss values are found to range in a ±5% interval around the reference values, with the lab-to-lab discrepancies chiefly descending from the heterogeneous variety of the employed magnetic circuits. Numerical analysis highlights the critical role of the effective field and its uniformity across the RSST sensing area. The statistical assessment of the laboratories' best estimates provides the empirical standard deviations s = 4.5% and s = 3.6% for the alternating and rotational loss figures, respectively, thereby showing a significantly reduced dispersion of the results compared with a previous international comparison launched in the '90s. It additionally points to the circular geometry for both sample and magnetizer as best suited for the prospective standardization of 2D measurements.</div
Augmentation and bulk edge correspondence for one dimensional aperiodic tight binding operators
No full textInternational audienceWe consider a particular class of 1D aperiodic models with the aim to understand how their internal degrees of freedom contribute to their topological invariants and the possible relations (correspondences) among them. In order to handle models with finite local complexity we introduce the principle of augmentation. This allows us to relate the values of the Integrated Density of States at gap energies for the bulk system to spectral flows. We consider two different augmentations. The first is based on the mapping torus construction. It leads to an alternative proof of the result that the gap labelling group of Bellissard coincides with that of Johnson-Moser. It furthermore allows for an interpretation of the spectral flow via boundary forces. The second augmentation applies to models obtained by the cut and project method where we find for 2-cut models two different spectral flows, one attached to the edge modes and related to the phason motion whereas the other is an augmented bulk invariant. Our approach is based on the well-established C * -algebraic approach to solid state physics and the description of topological invariants by K-theory and cyclic cocycles. We also present numerical simulations to illustrate our theorems
Approche multi-axes basée deep learning pour la segmentation 3D du diaphragme
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Evaluating Segmentation Using Betti-1 Topological Metric: Application to Nasal Cavities in the context of airflow simulation
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Quantum Mechanics on Lie Groups: I. Noncommutative Fourier Transforms
No full textInternational audienceStarting from square-integrable wave functions on a Lie group, we build an invertible Fourier transform mapping them on wave functions on the dual of the Lie algebra. This is a group-theoretic version of the map from position space to momentum space, with generally noncommuting momenta owing to the group structure. As a result, the multiplication of momentum-dependent functions involves star products, which makes the construction of noncommutative Fourier series much more involved than that of their commutative cousin. We show that our formalism provides an isometry of Hilbert spaces, and use it to derive a noncommutative Poisson summation formula for any compact Lie group. This is a key preliminary for the computation of Wigner functions and path integrals for quantum systems on group manifolds