bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical metamaterial sensors: from design to applications
Authors: de Souza Oliveira Hugo , Saeedzadeh Khaanghah Niloofar , Elli Giulia , Petti Luisa , Cantarella Giuseppe , Milana Edoardo , Münzenrieder Niko 
Published: January 2025

Abstract
The integration of mechanical metamaterials with sensor technology has opened new frontiers in the design and application of advanced sensing systems due to their ability to impart unique mechanical properties that enhance sensor functionality. Mechanical metamaterials, with properties derived from their engineered structures rather than their material composition, offer unique advantages such as negative Poisson’s ratio, high strength-to-weight ratios, and programmable behaviors. This review explores the dual approaches of incorporating sensors with mechanical metamaterials: metamaterial-supported sensors, where metamaterials provide structural support and enhanced durability to traditional sensors, and metamaterial-integrated sensors, where the metamaterial itself serves as the sensing element. Incorporating metamaterials in sensor design can offer increased sensitivity and precision, enhanced structural integrity and durability, programmability and reconfigurability, as well as lightweight and compact design solutions. Key advancements in the field are presented, highlighting how metamaterials properties can enhance sensor performance in terms of sensitivity, precision, and operational versatility. The review covers the primary materials and fabrication techniques used, including additive manufacturing, molding, and physical vapor deposition, and discusses the challenges associated with the mechanical integration of metamaterials and sensors. Practical applications in pressure, strain, temperature, and biomedical sensing are examined, demonstrating the transformative potential of mechanical metamaterials in creating high-performance, multifunctional sensor systems. The discussion concludes with an outlook on future research directions and potential advancements in the field.
Field emission study on atomically heterogeneous micro-metallic emitters produced by ion beam from inert gas plasmas
Authors: Majumdar Jayashree , Bhattacharjee Sudeep 
Published: January 2025

Abstract
High doses of irradiation in extreme environments, such as space or fusion reactors, cause significant substrate modifications, requiring systematic experimental data to understand the underlying processes. This study explores the effects of ion irradiation on aluminum and titanium sheets used in spacecraft, with fluence levels ranging from 3.8 to 3.9 × 1018 cm−2, employing 2 keV ions of argon and krypton generated by 2.45 GHz microwave plasma to investigate surface modifications and atomic heterogeneity induced by ion implantation, while minimizing complications from chemical bond formation. This experimental investigation is further extended to understand the impact of implanted ions and surface modifications on electron emission properties in high electric fields. Notable field emission improvements are observed: for krypton irradiated aluminum, turn-on potential is 2.3 ± 0.6 kV, a maximum current is 3.4 ± 0.3 nA, and enhancement factor is 1059, with krypton incorporation at 76.9

%

; for argon irradiated titanium, turn-on potential is 1.6 ± 0.2 kV, a maximum current is 9.8 ± 0.8 nA, and enhancement factor is 2540, with argon content at 88.5

%

. This study thus systematically discusses the discernible variations in field emission properties with the morphological changes, ion implantation percentages, and local work function measurements, providing valuable insights into the effects of inert gas ion irradiation on metallic substrates.
Solvent-modulated preparation of lead-free Cs3Bi2I9 polycrystalline film for high-performance photodetectors
Authors: Song Yaoyao , Zhang Huiyin , Liu Mengfan , Wan Yubo , Sun Hao , Cao Yang 
Published: January 2025

Abstract
Lead-free cesium bismuth iodide (Cs3Bi2I9) perovskite exhibits extraordinary optoelectronic properties and attractive potential in various optoelectronic devices, especially the application for photodetectors (PDs). However, most Cs3Bi2I9 PDs demonstrated poor detection performance due to the difficulty in obtaining high-quality polycrystalline films. Therefore, it makes sense to modulate the preparation of high-quality Cs3Bi2I9 polycrystalline films and expand its applications. Here, a solvent-modulated method combining anti-solvent and precursor engineering has been developed to regulate the crystallization dynamics of Cs3Bi2I9. Anti-solvent treatment is to suppress the asynchronous separation out of CsI and BiI3 due to significant differences in solubility, promoting uniform nucleation and limiting flake-like growth. Precursor engineering is synchronously used to modulate the subsequent nucleation growth dynamics. Due to the synergistic modulation, smooth and compact Cs3Bi2I9 polycrystalline films with distinct grains and grain boundaries can be easily obtained. The as-prepared PD exhibits an excellent on/off ratio of 4.26 × 105 as well as the detectivity up to 6.49 × 1010 Jones at zero bias. And, the Cs3Bi2I9 PD indicates excellent device stability, maintaining about 70% of the original performance after being stored for 400 h in the air without encapsulation.
Optimizing TMS dosimetry: evaluating the effective electric field as a novel metric
Authors: Colella Micol , Liberti Micaela , Carducci Filippo , Leodori Giorgio , Russo Giacomo Maria , Apollonio Francesca , Paffi Alessandra 
Published: January 2025

Abstract

Objective. This study introduces the effective electric field (E
eff) as a novel observable for transcranial magnetic stimulation (TMS) numerical dosimetry. E
eff represents the electric field component aligned with the local orientation of cortical and white matter (WM) neuronal elements. To assess the utility of E
eff as a predictive measure for TMS outcomes, we evaluated its correlation with TMS induced muscle responses and compared it against conventional observables, including the electric (E-)field magnitude, and its components normal and tangential to the cortical surface. Approach. Using a custom-made software for TMS dosimetry, the E
eff is calculated combining TMS dosimetric results from an anisotropic head model with tractography data of gray and white matter (GM and WM). To test the hypothesis that E
eff has a stronger correlation with muscle response, a proof-of-concept experiment was conducted. Seven TMS sessions, with different coil rotations, targeted the primary motor area of a healthy subject. Motor evoked potentials (MEPs) were recorded from the first dorsal interosseous muscle. Main results. The E
eff trend for the seven TMS coil rotations closely matched the measured MEP response, displaying an ascending pattern that peaked and then symmetrically declined. In contrast, the E-field magnitude and its components tangential (E
tan) and normal (E
norm) to the cortical surface were less responsive to coil orientation changes. E
eff showed a strong correlation with MEPs (r = 0.8), while the other observables had a weaker correlation (0.5 for E
norm and below 0.2 for E-field magnitude and E
tan). Significance. This study is the first to evaluate E
eff, a novel component of the TMS induced E-field. Derived using tractography data from both white and GM, E
eff inherently captures axonal organization and local orientation. By demonstrating its correlation with MEPs, this work introduces E
eff as a promising observable for future TMS dosimetric studies, with the potential to improve the precision of TMS applications.
A two-branch framework for blood pressure estimation using photoplethysmography signals with deep learning and clinical prior physiological knowledge
Authors: Qiao Minghong , Chang Li , Zhou Zili , Jun Sam Cheng , He Ling , Zhang Jing 
Published: January 2025

Abstract

Objective. This paper presents a novel dual-branch framework for estimating blood pressure (BP) using photoplethysmography (PPG) signals. The method combines deep learning with clinical prior knowledge and models different time periods (morning, afternoon, and evening) to achieve precise, cuffless BP estimation. Approach. Preprocessed single-channel PPG signals are input into two feature extraction branches. The first branch converts PPG dimensions to 2D and uses pre-trained Mobile Vision Transformer-v2 (MobileViTv2) and Visual Geometry Group19 (Vgg19) backbones to extract deep PPG features based on the different mechanisms of systolic blood pressure (SBP) and diastolic blood pressure (DBP) formation. The second branch calculates multi-dimensional feature parameters based on the relationship between PPG waveforms and factors affecting BP. We fuse the features from both branches and consider diurnal BP variations, using AutoML strategy to construct specific SBP and DBP estimation models for the different periods. The algorithm was developed on the human resting state PPG and BP dataset (HRSD) and validated on the MIMIC-IV dataset for generalization performance. Main results. The mean absolute error (MAE) for BP estimation is 6.42 mmHg SBP and 4.96 mmHg DBP in the morning, 4.84 mmHg (SBP) and 3.73 mmHg (DBP) in the afternoon, and 2.65 mmHg (SBP) and 2.56 mmHg (DBP) in the evening. Performance on the MIMIC-IV database was 4.34 mmHg (SBP) and 3.11 mmHg (DBP). The method meets the standards of the Association for the Advancement of Medical Instrumentation and achieves Grade A of the British Hypertension Society (BHS) standards. Significance. This indicates that it is an accurate and reliable non-invasive BP monitoring technology, applicable for continuous health monitoring and cardiovascular disease prevention.
Optical interferometry of high-energy nanosecond pin-to-pin discharges in atmospheric air
Authors: Babusis Nicholas , Jeong Won Joon , Shashurin Alexey 
Published: January 2025

Abstract
This paper describes the construction and application of an optical-frequency Michelson interferometer for measuring electron number density within high-energy, high-power nanosecond pin-to-pin discharges (>10 mJ pulse energy, >1 MW pulse power). A 21 mJ, 11 ns spark across a 3 mm pin-to-pin electrode gap was analyzed at 7 ns into the discharge to demonstrate the operation of the interferometer. A peak electron density of 2.3 × 1017 cm−3 was observed at these conditions, and it was consistent with estimates of plasma channel resistance based on V–I measurements. This initial work paves the way for a larger parametric study of the spatial and temporal dynamics of electron number density in nanosecond pin-do-pin discharges under various conditions.
Investigation of plasma decay in BP-HiPIMS discharges
Authors: Luo Yang , Han Mingyue , Wu Yiyan , Gao Pu , Li Liuhe 
Published: January 2025

Abstract
Investigation of the plasma decay mechanism from energy and density temporal/spatial evolutions together is important and urgent in the novel bipolar-pulse high power impulse magnetron sputtering (BP-HiPIMS) discharge for adjusting the deposited ion energy flux. In this work, temporal and spatial characteristics of the electron energy distribution function (EEDF) have been systematically investigated using a time-resolved (250 ns) Langmuir probe to obtain the plasma decay process clearly. The plasma decay has a typical characteristic of three-step during the positive pulse. At the initial period of positive pulse (Step 1), the existence of hot electrons and potential gradient force can accelerate the plasma density decay even up to ∼1015 m−3
μs−1. As the electron energy are cooled to several eVs, the plasma decay is dominated by the density gradient pressure with an ion sound velocity (0.5–0.7 kms−1), which can increase the downstream electron density (Step 2). As the redistribution of plasma density in the whole discharge domain, the electron density decay is exponential (Step 3) and the maximum decay rate is near the target due to the higher density gradient, while the maximum electron temperature is away from the target. Along the density gradient diffusion, the relation between electron density and temperature in BP-HiPIMS satisfies the well-known Boltzmann relation n
e = n
0exp(eV
p/kT
e). In addition, the EEDF characteristics in the BP-HiPIMS operated with an auxiliary anode and solenoid coil have also been investigated in this work, where an increase in electron density and plasma diffusion mobility has been observed after applying the anode or solenoid coil. These temporal and spatial EEDFs allow us to understand the complex plasma physics in the emerged BP-HiPIMS discharge clearly, especially with the view of high-energy and low-energy electron loss and balance.
The elastic frontier: dielectric elastomer actuators in healthcare technology
Authors: Benouhiba Amine , Holzer Simon , Konstantinidi Stefania , Civet Yoan , Perriard Yves 
Published: January 2025

Abstract
This review presents a detailed survey of Dielectric Elastomer Actuators (DEAs) and their emerging role in medical applications. DEAs are distinguished by their flexibility, low weight, and excellent biocompatibility, making them well-suited for a wide range of medical devices. The review explores the fundamental electro-mechanical principles behind DEA operation, which enable their remarkable ability to replicate natural muscle movements. Key applications discussed include biomedical devices, rehabilitation systems, in-vivo implants, and wearable health monitors, where DEAs offer dynamic, lifelike movements and precise control. Their ability to provide highly flexible and responsive actuation is a major advantage in medical technologies. However, challenges persist, particularly in terms of material durability, the need for high-voltage activation, and the integration of DEAs with existing medical technologies. By synthesizing recent research and highlighting ongoing hurdles, this review emphasizes the transformative potential of DEAs, offering a comprehensive look at their current state and future impact on next-generation medical devices.
Unveiling hidden geometric phase of neutron spin rotation in the Bitter–Dubbers experiment
Authors: Cheng Jian-Jian , Zhang Lin 
Published: January 2025

Abstract
We propose a novel framework to describe geometric phases in quantum systems under non-adiabatic conditions by introducing the concept of a hidden geometric phase. Conventional geometric phases, such as the Berry phase, rely on adiabatic evolution, limiting their applicability in rapidly changing systems. Here, we remove this constraint by reinterpreting the geometric phase as arising from a dynamically evolving reference basis, independent of the external topological features. The hidden phase is revealed through transitionless quantum control techniques, ensuring pure geometric phase accumulation even in non-adiabatic regimes. Our method offers an exact solution to the neutron spin rotation phase in the Bitter–Dubbers experiment, aligning more closely with experimental data without depending on adiabatic approximations. This unexpected result broadens our understanding of the geometric phase observed in neutron spin rotation beyond the adiabatic conditions that are conventionally required.
Irreversibility in non-reciprocal chaotic systems
Authors: Pham Tuan Minh , Alonso Albert , Proesmans Karel 
Published: January 2025

Abstract
How is the irreversibility of a high-dimensional chaotic system related to its dynamical behavior? In this paper, we address this question by developing a stochastic-thermodynamics treatment of complex networks that exhibit chaos. Specifically, we establish an exact relation between the averaged entropy production rate—a measure of irreversibility—and the autocorrelation function for an infinite system of neurons coupled via random non-reciprocal interactions. We show how, under given noise strength, the entropy production rate can signal the onset of a transition occurring as the coupling heterogeneity increases beyond a critical value via a change in its functional form upon crossing this point. Furthermore, this transition happens at a fixed, noise-independent entropy production rate, elucidating how robust energetic cost is possibly responsible for optimal information processing at criticality.
Low-power electrodeless 2.45 GHz microwave plasma generation in ambient air with dielectric resonators
Authors: Rossignol Noah , Wang Yaguo 
Published: January 2025

Abstract
Microwave (MW) plasma, as an electrodeless non-thermal plasma technique, holds significant potential for gas processing applications under near-ambient conditions. However, current MW plasma methods suffer from low energy efficiency due to the high power required for molecular breakdown via vibrational excitation. A promising approach to mitigate this challenge involves using a pair of high relative permittivity dielectric resonators (DRs) in close proximity to enhance the electric field within the small gap between them, thus reducing power consumption. In this study, we combined simulations and experiments to investigate the electric field enhancement effect of DRs with varying shapes, geometrical parameters (e.g., radius and height), gap distances, and orientations relative to the electric field polarization and MW propagation directions. Simulations performed using Ansys HFSS demonstrate that edge-to-edge configurations of hexagonal, square, and triangular prism DRs can achieve significant electric field enhancement over a broad range of geometric parameters. DRs fabricated from calcium titanate were tested experimentally using a simple setup with a kitchen microwave (2.45 GHz) at ambient pressure. With input power below 100 W, stable and highly confined plasma was generated using hexagonal and triangular prism DRs. These results suggest a simple, cost-effective, and low-power method for generating MW plasma under ambient conditions, offering particular advantages for chemical processing in rural areas utilizing renewable energy resources.
A hybrid CMOS-memristor based adaptable Bidirectional Associative Memory neural network for pattern recognition applications
Authors: S Shekinah Archita , V Ravi 
Published: January 2025

Abstract
This research presents a circuit-level hybrid CMOS memristor architecture for constructing Bidirectional Associative Memory (BAM). Initially, a synaptic circuit structure was built by employing a voltage threshold memristor in a crossbar architecture. This synaptic structure is adaptable and flexible for generating a wide range of synaptic weights. It is then deployed in the BAM network to perform an associative function. To aid in better name recall, this BAM network has been trained to associate Greek and mathematical symbols with their first letters in English, and vice versa. The designed circuit was validated using MATLAB and the EDA (Electronic Design Automation) Tool: Cadence Virtuoso. The addition of noise further evaluates the performance of the BAM network. When tested with noise levels of 10%, 20%, and 30%, the input patterns were retrieved at 100% in both directions. Furthermore, the proposed synaptic circuit is validated for variations in R

ON
, R

OFF
and it’s performance is compared with other memristor models. It is also found that the average power consumption of the proposed synatic circuit is 1.22 mW. These results, which were experimentally confirmed, demonstrate the precision and noise isolation of the proposed BAM design. With appropriate tuning of memristor, the synaptic weights can be mapped easily with the memristor conductance value. This circuit can be effectively used in the field of image processing, neural network and neuromorphic computation which helps to associate and restore original or damaged binary images, showing strong robustness and accuracy.
BCS: A neural distinguisher method based on differential propagation uncertainty of nonlinear components and network adaptability
Authors: Zhu Siqi , Li Lang , Hu Zhiwen , Hu Yemao 
Published: January 2025

Abstract
The neural distinguisher (ND) is the combined product of differential cryptanalysis and deep learning. Its emergence has greatly promoted the development of differential cryptanalysis. Current approaches to improving the performance of NDs focus on data input formats and training frameworks. However, many researchers independently focused on enhancing the data input format or training framework, neglecting their adaptability to each other. Additionally, little research has focused on improving the data input format based on its correlation with the components of the cipher. This paper proposes an ND called the Block Cipher with S-box (BCS) model to address these issues. The model uses new data input formats, Add S-box Multiple Ciphertext Pairs (ASMCP) and Add S-box Multiple Output Difference (ASMOD), along with an improved U-Net network. These two formats are developed based on the decapsulated encryption process method and incorporate the input and output features of the S-box component to increase the available features. The improved U-Net network incorporates long-range skip-connections, better suited for new data input formats. Comparative experiments demonstrate that the BCS model achieves higher distinguishing accuracy and reduces the model size. Finally, the BCS model is applied to key recovery attacks on 8-round PRESENT with a success rate of 98%.
Write error ballooning due to anisotropy variation within the free layer in perpendicular magnetic tunnel junctions
Authors: Nisar Arshid , Arya Susheel K , Kaushik Brajesh K , Pramanik Tanmoy 
Published: January 2025

Abstract
A finite-temperature micromagnetic investigation is conducted to analyze magnetization switching and write error rates in perpendicular spin-transfer torque random access memory (STT-RAM), including the influence of domain wall (DW) pinning arising from variations within the free layer (FL) magnet and stray field from reference layer assembly in the magnetic tunnel junction. The study reveals that uneven perpendicular magnetic anisotropy within the FL could lead to the formation of pinning sites that give rise to metastable states during switching. Such metastable states could result in a significant increase in the write error rates as compared to the ideal situation. Unlike the case with stray fields arising from reference layer assembly, where the DW propagation is hindered only for one switching direction, inhomogeneity within the FL causes the DW pinning to occur in both switching directions. Combined effects of FL inhomogeneity and stray field from the reference layer result in write error ballooning similar to those reported in recent experiments. The impact of free layer inhomogeneity could be further exacerbated by the stray field for one of the switching directions. Surprisingly, the impact of inhomogeneity is also observed to persist at smaller FL dimensions where quasi-coherent switching is expected. These findings provide deeper insights into the potential factors contributing to anomalous write errors in perpendicular STT-RAM.
The electron tunneling effect on the diffraction pattern of the QD-cavity optomechanical system
Authors: Feng Shuling , Ding Zhilin 
Published: January 2025

Abstract
We theoretically analyze the phenomenon of optomechanically induced grating of a weak probe field in a hybrid optomechanical system, consisting of an optical cavity, a mechanical resonator and quantum dot molecules (QDs). We found that for a standing wave pattern of the driving light, the transmission and phase functions of the probe light can be changed periodically which in some parameter regimes their values can exceed unity. Furthermore, the Fraunhofer diffraction pattern of the weak probe light at the resonance frequency have been studied. Therefore, we can control the transfer of the probe energy from zero order to the higher orders of the diffraction by tuning the electron tunneling and driving field attributed to quantum interference. Our simulations may provide a flexible way to control optical response and propagation in such a hybrid optomechanical system.