HAL Université de Savoie
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Design of a Compact Low Power 10 nF Capacitance Multiplier for Biomedical Applications
No full textInternational audienceIn many biomedical circuits, such as notch filters, relaxation oscillators, H-bridge stimulation circuits, and voltage multiplication, large capacitance values are often required. However, integrating such capacitors on-chip presents significant challenges due to the extensive silicon area they occupy. Capacitance multipliers have been proposed to address this issue, though the inclusion of active elements typically results in increased power consumption. To mitigate this, a low-power Gm-based capacitance multipliers, which operates in weak inversion region to minimize the bias current and power consumption, is presented in this paper. The proposed circuit achieves a multiplication factor of 10000, leading to an effective capacitance of 10 nF based on a 1 pF integrated MIM capacitor. Post layout simulation result shows that it operates with very low average power consumption of 56.74 nW and occupies a compact area of 92.545 µm×35 µm, in contrast to the 1 mm² required for a 1 nF capacitor in a 0.18 µm CMOS process
19th-century afforestation policies have predisposed mountain slopes to forest expansion under recent climate warming in the southern French Alps
No full textInternational audienceThis interdisciplinary study investigates the long-term interplay between forests, human societies, and climate in Abriès-Ristolas (Queyras massif, southern French Alps) over the past 200 years. Drawing on archival records, dendrochronology, satellite-derived vegetation indices, and climate data, we trace the historical legacies that have shaped contemporary land cover and forest dynamics. Our findings show that recent forest expansion and land greening – often attributed solely to climate change – are also the outcome of 19th-century socio-economic shifts and environmental policies. Specifically, we find that spatial variability in greening trends aligns with the historical structure of cadastral parcels, highlighting persistent land-use effects. The 1860 Mountain Reforestation Law, locally implemented by an 1864 decree, combined with rural depopulation and a decline in pastoral activities, significantly reduced anthropogenic pressure, facilitating natural forest regeneration in this area. These historical transformations have predisposed the landscape to continued forest expansion, with recent climate warming further amplifying this trajectory over the past four decades. This case study underscores the importance of incorporating land-use legacies into interdisciplinary approaches for understanding present-day ecological change
Low-temperature, high-throughput spatial atomic layer deposition of NiOx nanocrystalline thin films from [Ni(ipki)2]
No full textInternational audienceSpatial atomic layer deposition (SALD) is a recent ALD variant enabling much faster deposition rates, even at atmospheric pressure, making it ideal for scalable, low-cost devices. NiO x , a transparent p-type oxide, is widely used in emerging technologies like perovskite solar cells. However, no suitable SALD process for NiO thin films has been reported so far. In this work, we present the deposition of nanocrystalline NiO x thin films via SALD using a recent Ni precursor not yet explored for the ALD of NiO, namely, bis(4-(isopropylamino)pent-3en-2onato)nickel(II) or [Ni( i pki) 2 ]. O 2 has been used as coreactant, with higher deposition rates being achieved if H 2 O is added to the O 2 flow. A narrow ALD window has been obtained between 230 • C and 250 • C, where a GPC of 0.023 nm is observed. This corresponds to a deposition rate of 1.4 nm/min, which is 2 to 10 times faster than the rates reported for conventional ALD of NiO thin films. Remarkably, the growth onset of NiO x starts around only 170 • C. The transmittance of the films reaches nearly 97 % in the visible for 55 nm thick films. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies revealed a high homogeneity of the films. X-ray diffraction (XRD), Raman spectroscopy and X-ray absorption spectroscopy (XAS) studies confirm the presence of a cubic NiO x crystalline phase. Finally, NiO x films have been deposited on Ag nanowire networks, demonstrating the possibility of depositing homogeneous and conformal coatings with this new process
Une cartographie de l'état de la connaissance sur l'évaluation de la trajectoire de dépôt par DED-WAAM
No full textInternational audienceUne cartographie de l'état de la connaissance sur l'évaluation de la trajectoire de dépôt par DED-WAA
Environmental exposure to endocrine disruptors induces insulin resistance and hepatic inflammation in adult male rats, with partial transmission across subsequent generations
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Réflexions sur l'accueil du sexe neutre en droit international privé (à propos de la décision du Tribunal fédéral suisse du 8 juin 2023)
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Analysis of 2PACz functionalization of different ITO layers using an e-beam-based technique for work function measurement
No full textInternational audienceIn recent years, phosphonic-acid-carbazole-based self-assembled monolayers (PACz SAMs) have become standard as hole-selective layers in inverted perovskite solar cells (PSC) and perovskite-on-silicon tandem devices. PACz SAMs covalently bond to the transparent conductive oxide (TCO) on which they are deposited, typically an indium tin oxide (ITO) layer, thereby increasing the work function (WF) of the ITO surface and enabling hole extraction from the perovskite absorber. The properties of the underlying ITO layer can affect the functionalization of its surface by SAMs, and while there is an increasing number of studies to understand this aspect, the ITO properties required for good functionalization are unclear. This article investigates the effectiveness of ITO functionalization by 2PACz by using an original electron-beam-based technique that directly reveals the ability of a sample to repel electrons and allows the calculation of the sample WF. We compare two different ITO layers: a commercially available, polycrystalline ITO layer with a thin, in-house deposited amorphous ITO layer, typically used as recombination layer in perovskite/silicon tandem solar cells. The e-beam-based measurement reveals significantly different work function shifts after 2PACz functionalization, in agreement with the observed PSC performances. This difference is discussed in terms of ITO layer properties and surface chemistry. Overall, this works highlights the importance of taking into account optimal carrier selection in the optimization of TCObased recombination junctions
VLSI piezoelectric optomechanics for GHZ time references
No full textInternational audienceOscillators based on optomechanical resonators have emerged as high-performance alternative for time references at the GHz, but their integration with compact electronics remains a challenge. Current implementations present either off-chip actuation the resonators or inefficient on-chip methods requiring important actuation voltages, both incompatible with integrated electronics. Here we present an alternative based on piezoelectric (AlN) based optomechanics, providing state-of-the-art phase noise (-125 dBc/Hz @ 280 MHz) with an actuation voltage of only 100 mV. The demonstrator was fabricated with a VLSI technology specifically developed for sensors and time references in a semi-industrial clean room
Comparable outcomes and early revision rates between restricted and unrestricted functional knee positioning in robotic‐assisted total knee arthroplasty for varus deformities ≥10°
No full textInternational audienceAbstract Purpose Functional knee positioning (FKPos) in total knee arthroplasty (TKA) optimises outcomes by balancing individual anatomical and soft tissue characteristics. Managing marked varus deformity presents challenges in achieving balance when tibial alignment is restricted to 3° of varus, necessitating either medial soft tissue release or unrestricted tibial positioning. This study aims to compare restricted FKPos with medial soft tissue release to unrestricted FKPos without soft tissue release in patients with varus deformity ≥10 ° . Methods This retrospective, two‐center study analysed robotic‐assisted TKAs. Patients were categorised into two groups: restricted FKPos with medial soft tissue release (Group A) and unrestricted FKPos without soft tissue release (Group B). Inclusion criteria required a preoperative coronal alignment of ≥10° varus. Outcomes included Knee Society Scores (KSS), Forgotten Joint Scores (FJS), complications, and implant survivorship over a median follow‐up of 38 months (interquartile range [IQR] 30–45). Results A total of 205 patients (Group A: 71 and Group B: 134) were included. No significant differences were observed in functional outcomes (KSS and FJS) or complication rates between the groups. Median tibial varus alignment was 1° in Group A and 4.5° in Group B ( p < 0.0001). Implant survivorship was comparable between groups (1.4% in Group A and 0.75% in Group B; p = 0.65; hazard ratio = 1.94; 95% confidence interval: 0.11–35.62). Conclusion This study demonstrated that restricted FKPos with medial soft tissue release and unrestricted FKPos without soft tissue release result in comparable short‐term outcomes, complication rates, and implant survivorship in ≥10° varus deformities. While these findings suggest that unrestricted tibial positioning may be a promising alternative to traditional approaches, further studies with long‐term follow‐up are needed to confirm its safety and durability. Level of Evidence Level III