bluuebunny/crossref_metadata_2025 huggingface dataset:
From minimal strings towards Jackiw–Teitelboim gravity: on their resurgence, resonance, and black holes
Authors: Gregori Paolo , Schiappa Ricardo
Published: March 2024

Two remarkable facts about Jackiw–Teitelboim (JT) two-dimensional dilaton-gravity have been recently uncovered: this theory is dual to an ensemble of quantum mechanical theories; and such ensembles are described by a random matrix model which itself may be regarded as a special (large matter-central-charge) limit of minimal string theory. This work addresses this limit, putting it in its broader matrix-model context; comparing results between multicritical models and minimal strings (i.e. changing in-between multicritical and conformal backgrounds); and in both cases making the limit of large matter-central-charge precise (as such limit can also be defined for the multicritical series). These analyses are first done via spectral geometry, at both perturbative and nonperturbative levels, addressing the resurgent large-order growth of perturbation theory, alongside a calculation of nonperturbative instanton-actions and corresponding Stokes data. This calculation requires an algorithm to reach large-order, which is valid for arbitrary two-dimensional topological gravity. String equations—as derived from the Gel’fand–Dikii construction of the resolvent—are analyzed in both multicritical and minimal string theoretic contexts, and studied both perturbatively and nonperturbatively (always matching against the earlier spectral-geometry computations). The resulting solutions, as described by resurgent transseries, are shown to be resonant. The large matter-central-charge limit is addressed—in the string-equation context—and, in particular, the string equation for JT gravity is obtained to next derivative-orders, beyond the known genus-zero case (its possible exact-form is also discussed). Finally, a discussion of gravitational perturbations to Schwarzschild-like black hole solutions in these minimal-string models, regarded as deformations of JT gravity, is included—alongside a brief discussion of quasinormal modes.
Elucidating the coherent and incoherent reflection of plane-waves in finite thickness media: a practical pedagogical application
Authors: Villegas Cesar E P , Romero-Abad David , Rojas Wudmir Y
Published: March 2024

The propagation of light through a thin film interfaced between two semi-infinite media serves as a compelling illustration for elucidating electromagnetic wave interactions with matter at the undergraduate level. Despite its pedagogical significance and diverse technological applications, this model often receives inadequate attention in foundational electromagnetism literature, limiting early student exposure to this emblematic concept. In this pedagogical initiative, we present a comprehensive analysis of electromagnetic wave propagation through a dielectric medium positioned between semi-infinite media. We examine interference phenomena arising from back-and-forth reflected waves within the dielectric, focusing on the coherent and incoherent reflection regimes as limiting cases. Employing rigorous analytical treatment, we delineate transmittance and reflectance profiles, offering students a lucid understanding of how the refractive index’s real and imaginary components compete and manifest under specific conditions. This analytical approach enhances students’ comprehension of electromagnetic wave behavior within diverse mediums. Furthermore, we extend this theoretical foundation to practical applications, emphasizing renewable energy contexts. By calculating absorptance, we estimate the maximum photo-generated current and power conversion efficiency of a prototype solar cell, establishing a tangible link between theoretical knowledge and real-world solar energy utilization.
Inverse spectral problem for the Schrödinger operator on the square lattice
Authors: Wu Dongjie , Yang Chuan-Fu , Bondarenko Natalia Pavlovna
Published: March 2024

We consider an inverse spectral problem on a quantum graph associated with the square lattice. Assuming that the potentials on the edges are compactly supported and symmetric, we show that the Dirichlet-to-Neumann map for a boundary value problem on a finite part of the graph uniquely determines the potentials. We obtain a reconstruction procedure, which is based on the reduction of the differential Schrödinger operator to a discrete one. As a corollary of the main results, it is proved that the S-matrix for all energies in any given open set in the continuous spectrum uniquely specifies the potentials on the square lattice.
Plasmonic gas sensors based on nanomaterials: mechanisms and recent developments
Authors: Vaidyanathan Antara , Mondal Brinti , Rout Chandra Sekhar , Chakraborty Brahmananda
Published: March 2024

Sensing devices for rapid analytics are important societal requirements, with wide applications in environmental diagnostics, food testing, and disease screening. Nanomaterials present excellent opportunities in sensing applications owing to their superior structural strength, and their electronic, magnetic, and optoelectronic properties. Among the various mechanisms of gas sensing, including chemiresistive sensors, electrochemical sensors, and acoustic sensors, another promising area in this field involves plasmonic sensors. The advantage of nanomaterial-plasmonic sensors lies in the vast opportunities for tuning the sensor performance by optimizing the nanomaterial structure, thereby producing highly selective and sensitive sensors. Recently, several novel plasmonic sensors have been reported, with various configurations such as nanoarray resonator-, ring resonator-, and fibre-based plasmonic sensors. Going beyond noble metals, some promising nanomaterials for developing plasmonic gas sensor devices include two-dimensional materials, viz. graphene, transition metal dichalcogenides, black phosphorus, blue phosphorus, and MXenes. Their properties can be tuned by creating hybrid structures with layers of nanomaterials and metals, and the introduction of dopants or defects. Such strategies can be employed to improve the device performance in terms of its dynamic range, selectivity, and stability of the response signal. In this review, we have presented the fundamental properties of plasmons that facilitate its application in sensor devices, the mechanism of sensing, and have reviewed recent literature on nanomaterial-based plasmonic gas sensors. This review briefly describes the status quo of the field and prospects.
Recent advances in in-sensor computational vision sensors: from mechanisms to applications
Authors: Xu Hang , Meng Leixin , Guo Yiyu , Tang Wenhao , Huang Liangliang , Dai Tiantian , Liu Xu , Yang Qing
Published: March 2024

The number of vision sensors continues to increase with the rapid development of intelligent systems. The effective transmitting and processing of the sensing data become difficult due to the sensing, computing and memory units being physically separated. In-sensor computing architecture inspired by biological visual systems with efficient information processing has attracted increasing attention for overcoming these performance limitations. Bipolar cells in the retina can generate ON/OFF information processing channels to amplify marginal information. The synaptic structure is plastic and can enhance the output information that is repeated many times. In recent years, numerous new material and device strategies to implement in-sensor computing by mimicking the functions of bipolar cells and synapses have been reported: ON/OFF optical responses have been realized on two-dimensional materials by band-modulation and tunneling; synaptic responses, such as short-term plasticity and long-term plasticity, have been realized by phase transition and carrier regulating. In this review, we will summarize the biological vision processes, analyse the physical mechanisms behind the in-sensor computational vision sensors (ICVSs), and then overview the emerging physical artificial neural networks implemented with ICVSs. After that, we will discuss ICVS design based on biological mechanisms beyond ON/OFF bipolar-cell-response and synaptic response.
The modulation of perpendicular magnetic anisotropy and spin–orbit toque in Pt/Co/Pt multilayers with interfacial decoration by insertion of a Bi layer
Authors: Wu Yong , Wen Kaibin , Zhang Tanzhao , Liu Ye , Meng Kangkang , Xu Xiaoguang , Jiang Yong
Published: March 2024

Bismuth is a well-known semimetal material with strong spin–orbit coupling and has been confirmed to exhibit a larger spin Hall angle in CuBi and PtBi alloys with low Bi-doping concentration. In this study, we investigated perpendicular magnetic anisotropy (PMA) and spin–orbit torques (SOTs) in Pt/Co/Pt multilayers by inserting a Bi layer with a thickness of 2 nm at the Co/Pt interface. Two types of PMA multilayers, Pt (3 nm)/Co (1 nm)/Pt (5 nm) and Pt (3 nm)/Co (1 nm)/Pt (1 nm), with different spin accumulations, were designed and prepared by varying the top Pt thickness. A significant enhancement of PMA and SOT efficiency is observed in the Pt (3 nm)/Co (1 nm)/Bi (2 nm)/Pt (5 nm) multilayer via a Bi-layer interfacial decoration. However, for the Pt (3 nm)/Co (1 nm)/Bi (2 nm)/Pt (1 nm) multilayers, both PMA and SOT efficiency decrease with decoration of the Bi layer at the Co/Pt interface. Meanwhile, the sign of SOTs changes in the Pt (3 nm)/Co (1 nm)/Pt (5 nm) and Pt (3 nm)/Co (1 nm)/Pt (1 nm) multilayers when introducing a Bi layer. This completely opposite behavior illustrates that the Bi/Pt interface plays an important role in modulating the PMA and SOT efficiency of Pt/Co/Bi/Pt multilayers. Optimizing the alloying of Bi/Pt could be an effective approach to increase the PMA and SOT efficiency of Pt/Co/Bi/Pt multilayers.
Ultra-sensitive fiber optic sensor for glucose concentration measurement based on Vernier effect in cascaded Mach–Zehnder interferometers
Authors: Zhang Sa , Chen Hailiang , Fan Xiaoya , Li Hongwei , Li Lida , Shi Ruyue , Gu Mingqi , Li Shuguang
Published: March 2024

In this paper, a fiber optic glucose concentration sensor based on cascaded Mach–Zehnder interferometers (CMZIs) was proposed and experimentally verified. Two single-mode fibers (SMFs) with slightly different tapering lengths and as well free spectral ranges (FSRs) were obtained through the melt-drawn cones technique and then were cascaded together to achieve the Vernier effect (VE). Experimental results showed that the measurement sensitivity of glucose concentration based on a single tapered SMF was 0.0494 nm (mmol l−1)−1. Furthermore, the measurement sensitivity based on the cascaded tapered SMFs was enhanced by 4.86 times to an ultra-high level of 0.2402 nm (mmol l−l)−1. The resolution reached 0.083 mmol l−1. The refractive index sensitivity reached 9066 nm/RIU. The resolution reached 2.21 × 10−6 RIU. In addition, the proposed glucose concentration sensor based on CMZIs shows good hysteresis. In conclusion, the designed sensor, showing the merits of easy to fabricate, high sensitivity, and high detection resolution, could be used to monitor the tiny variation in glucose concentration.
Klein–Gordon particles in a quasi-pointlike global monopole spacetime and a Wu-Yang magnetic monopole: invariance and isospectrality
Authors: Mustafa Omar
Published: March 2024

We use two correlated metric functions and transform/deform the pointlike global monopole (PGM) spacetime metric into a quasi-PGM (QPGM) spacetime one. We study Klein–Gordon (KG) particles (manifestly introduced by the non-minimal coupling form of the operator

D

˜

μ

=

D

μ

+

F

μ

, with

F

μ

∈

R

, and D

μ
= ∂
μ
− ie
A

μ
) in such QPGM spacetime background. We show that the KG-particles in the QPGM spacetime are isospectral and invariant with KG-particles in the PGM spacetime, provided that the two metric functions are correlated. The Wu-Yang magnetic monopole (WYMM) is also included in the process. We report the effects of both monopoles PGM/QPGM and WYMM on the spectroscopic structure of two models, KG-oscillators and KG-Coulomb particles in such spacetime background. Moreover, we discuss KG-Coulomb particles and shifted KG-oscillators in a PGM spacetime and a WYMM, where such models are manifestly introduced by some Lorentz scalar interaction potentials S(r). The current study is not only of fundamental observability nature but also of pedagogical interest in quantum gravity.
Magnetic exchange interactions at the proximity of a superconductor
Authors: Aceves Rodriguez Uriel A , Guimarães Filipe , Brinker Sascha , Lounis Samir
Published: March 2024

Interfacing magnetism with superconductivity gives rise to a wonderful playground for intertwining key degrees of freedom: Cooper pairs, spin, charge, and spin–orbit interaction, from which emerge a wealth of exciting phenomena, fundamental in the nascent field of superconducting spinorbitronics and topological quantum technologies. Magnetic exchange interactions (MEIs), being isotropic or chiral such as the Dzyaloshinskii–Moriya interactions, are vital in establishing the magnetic behavior at these interfaces as well as in dictating not only complex transport phenomena, but also the manifestation of topologically trivial or non-trivial objects. Here, we propose a methodology enabling the extraction of the tensor of MEI from electronic structure simulations accounting for superconductivity. We apply our scheme to the case of a Mn layer deposited on Nb(110) surface and explore proximity-induced impact on the MEI. The latter are weakly modified by a realistic electron-phonon coupling. However, tuning the superconducting order parameter, we unveil potential change of the magnetic order accompanied with chirality switching, as induced by the interplay of spin-orbit interaction and Cooper pairing. Owing to its simple formulation, our methodology can be readily implemented in state-of-the-art frameworks capable of tackling superconductivity and magnetism. We thus foresee implications in the simulations and prediction of topological superconducting bits as well as of cryogenic superconducting hybrid devices involving magnetic units.
Features extraction of point clouds based on Otsu’s algorithm
Authors: He Yibo , Hu Zhenqi , Wang Rui , Zhu Haizhong , Fu Guilin
Published: March 2024

Currently, a point cloud extraction method based on geometric features requires the configuration of two essential parameters: the neighborhood radius within the point cloud and the criterion for feature threshold selection. This article addresses the issue of manual selection of feature thresholds and proposes a feature extraction method for 3D point clouds based on the Otsu algorithm. Firstly, the curvature value of each point cloud is calculated based on the r-neighborhood of the point cloud data. Secondly, the Otsu algorithm is improved by taking the curvature values as input for the maximum inter-class variance method. The optimal segmentation threshold is obtained based on the Otsu algorithm to divide the point cloud data into two parts. Point cloud data whose curvature is greater than or equal to the threshold is extracted as feature point data. In order to verify the reliability of the algorithm presented in this paper, a method for accuracy assessment of regular point cloud data is proposed. Additionally, comparative analysis was conducted on data with varying point cloud densities and on data contaminated with Gaussian white noise using multiple methods. Experimental results show that the proposed algorithm achieves good extraction results for data with 90% simplification rate and low noise.
Power transformer fault diagnosis using dynamic multiscale graph modeling and M2SGCN network based on statistical fusion
Authors: Liu Xiaoyan , He Yigang
Published: March 2024

Power equipment fault diagnostics hold significant importance for the stability of power grid systems. In pursuit of this objective, this paper proposes a fault diagnosis method that utilizes dynamic multiscale graph (DMG) modeling and the multiscale multi-stream GCN(M2SGCN) network, incorporating statistical fusion. Specifically, a novel DMG modeling method is proposed to derive visibility graph data and horizontal visibility graph data from vibration signals across multiple scales. Next, a comprehensive neural network architecture named M2SGCN is established to learn global and local features simultaneously, providing a more precise representation. Subsequently, a Dempster Shafer evidence theory statistical fusion technique combined with an adaptive threshold model (DSTFusion) is utilized to integrate primary decision results for enhanced fault diagnosis accuracy. In addition, two datasets obtained from single-phase and three-phase power transformers are analyzed to demonstrate the evolution process. When compared to state-of-the-art indicators such as accuracy, precision, recall, and F1 scores, the method proposed excels in multiple aspects, successfully detecting fault states before their occurrence and achieving outstanding performance.
Modeling and simulation of anisotropic cross-linked cellulose fiber networks with an out-of-plane topography
Authors: Agarwal Shubham , Green Sheldon I , Phani A Srikantha
Published: March 2024

Non-woven cellulose fiber networks of low areal density are widely used in many industrial applications and consumer products. A discrete element method (DEM) modeling framework is advanced to simulate the formation of strongly anisotropic cellulose fiber network sheets in the dilute limit with simplified hydrodynamic and hydroelastic interactions. Our modeling accounts for in-plane fiber orientation and viscous drag indirectly by using theories developed by Niskanen (2018 Fundamentals of Papermaking, Trans. 9th Pulp and Paper Fundamental Research Symp. Cambridge, 1989 (FRC) pp 275–308) and Cox (1970 J. Fluid Mech.
44 791–810) respectively. Networks formed on a patterned and flat substrate are simulated for different fiber types, and their tensile response is used to assess the influence of the out-of-plane topographical pattern, specifically, on their stiffness and strength. Sheets with the same grammage and thickness, but composed with a higher fraction of softwood fiber (longer fibers with large diameter), have higher strength and higher strain to failure compared to sheets made from hardwood fibers (short fibers with small diameter). However, varying the fiber fraction produces only an insignificant variation in the initial sheet stiffness. The above simulation predictions are confirmed experimentally for sheets comprised of fibers with different ratios of Eucalyptus kraft and Northern Bleached Softwood Kraft fibers. Sheets with out-of-plane topography show an unsymmetric mass distribution, lower tensile stiffness, and lower tensile strength compared to those formed on a flat substrate. The additional fiber deformation modes activated by the out-of-plane topography, such as bending and twisting, explain these differences in the sheet mechanical characteristics.
The composition effect on the structural and thermodynamic properties of Cu–Ag–Au ternary nanoalloys: a study via molecular dynamics approach
Authors: Cuba-Supanta Gustavo , Amao P , Quispe-Huaynasi F , Pinto-Vergara M Z , Pacheco Elluz , Flores S Y , Soncco C , Loaiza-Tacuri V , Rojas-Tapia J
Published: March 2024

Metal ternary nanoalloys or trimetallic nanoparticles have emerged, in recent years, as novel and relevant materials in different fields due to the synergy of three metals in a single system that leads to unique physicochemical properties as compared to mono- and bimetallic nanoparticles. In this study, the influence of composition on the structural and thermodynamic properties of Cu–Ag–Au nanoalloys with 5083 atoms is analyzed using molecular dynamics simulations. Relevant thermodynamic quantities are used to describe the melting and solidification behaviors of three models of Cu–Ag–Au nanoalloys. Our results indicate that the melting temperature presents linear and quadratic dependencies with the composition, i.e. for Cu33Ag

67
−
x

Au
x
, Ag33Cu

67
−
x

Au
x
, and Au33Ag

67
−
x

Cu
x
are

T
m

=
912.6
+
1.9
x

,

T
m

=
882.3
+
2.7
x

, and

T
m

=
1056.6
−
4.9
x
+
0.07

x
2

, respectively. In addition, most Ag atoms segregate to the surface and the Au and Cu atoms are localized in the center of the nanoalloy during the heating process, and this trend is maintained in the cooling process. The solidification temperature does not have an explicit correlation with the composition. Furthermore, the structural analysis of cooled nanoalloys exhibits local FCC and HCP symmetries, and the excess energy shows that Cu33Ag27Au40, Au33Ag17Cu50, and Ag33Cu37Au30 are relatively more stable to form nanoalloys. Finally, the possibility of controlling the composition in these metal nanoalloys opens up potential applications in plasmonic, catalysis, and bactericidal (by Ag surface segregation) fields.
Advances in selenium from materials to applications
Authors: Liu Hao , Chen Liping , Shen Yunkun , Fan Li , Zhang Jiawei , Zhu Hongliang , Shi Yi , Yan Shancheng
Published: March 2024

Over the past few decades, single-element semiconductors have received a great deal of attention due to their unique light-sensitive and heat-sensitive properties, which are of great application and research significance. As one promising material, selenium, being a typical semiconductor, has attracted significant attention from researchers due to its unique properties including high optical conductivity, anisotropic, thermal conductivity, and so on. To promote the application of selenium nanomaterials in various fields, numerous studies over the past few decades have successfully synthesized selenium nanomaterials in various morphologies using a wide range of physical and chemical methods. In this paper, we review and summarise the different methods of synthesis of various morphologies of selenium nanomaterials and discuss the applications of different nanostructures of selenium nanomaterials in optoelectronic devices, chemical sensors, and biomedical applications. Finally, we discuss possible challenges for selenium nanodevices and provide an outlook on the future applications of selenium nanomaterials.
Surface termination modulation for superior S-Scheme Bi2WO6/BiOI heterojunction photocatalyst: a hybrid density functional study
Authors: Nie Hongwei , Liu Zuoyin , Kong Bo , Xu Xiang , Wang Wentao
Published: March 2024

The prevailing theoretical frameworks indicate that depending on the growth conditions, the Bi2WO6(001) surface can manifest in three distinct terminations—DL-O–Bi (DL: double layers), O–Bi, and O–W. In this study, we conduct a comprehensive examination of the interplay between these terminations on Bi2WO6(001) and the 1I-terminated BiOI(001) facet, especially focusing on their impact on the photocatalytic activity of Bi2WO6/BiOI heterostructure, applying hybrid functional calculations. The models formulated for this research are designated as Bi2WO6(O–Bi)/BiOI(1I), Bi2WO6(DL-O–Bi)/BiOI(1I), and Bi2WO6(O–W)/BiOI(1I). Our findings reveal that Bi2WO6(O–Bi)/BiOI(1I) shows a type II band alignment, which facilitates the spatial separation of photo-generated electrons and holes. Notably, the Bi2WO6(DL-O–Bi)/BiOI(1I) configuration has the lowest binding energy and results in an S-scheme (or Step-scheme) heterostructure. In contrast to the type II heterostructure, this particular configuration demonstrates enhanced photocatalytic efficiency due to improved photo-generated carrier separation, augmented oxidation capability, and better visible-light absorption. Conversely, Bi2WO6(O–W)/BiOI(1I) presents a type I projected band structure, which is less conducive for the separation of photo-generated electron–hole pairs. In summation, this investigation points out that one could significantly refine the photocatalytic efficacy of not only Bi2WO6/BiOI but also other heterostructure photocatalysts by modulating the coupling of different terminations via precise crystal synthesis or growth conditions.
Formation of singularities in plasma ion dynamics
Authors: Bae Junsik , Choi Junho , Kwon Bongsuk
Published: March 2024

We study the formation of singularity for the Euler–Poisson system equipped with the Boltzmann relation, which describes the dynamics of ions in an electrostatic plasma. In general, it is known that smooth solutions to nonlinear hyperbolic equations fail to exist globally in time. We establish criteria for C
1 blow-up of the Euler–Poisson system, both for the isothermal and pressureless cases. In particular, our blow-up condition for the pressureless model does not require that the gradient of velocity is negatively large. In fact, our result particularly implies that the smooth solutions can break down even if the gradient of initial velocity is trivial. For the isothermal case, we prove that smooth solutions leave C
1 class in a finite time when the gradients of the Riemann functions are initially large.
Evaluating the relationship between contouring variability and modelled treatment outcome for prostate bed radiotherapy
Authors: Le Bao Viet , Haworth Annette , Dowling Jason , Walker Amy , Arumugam Sankar , Jameson Michael , Chlap Phillip , Wiltshire Kirsty , Keats Sarah , Cloak Kirrily , Sidhom Mark , Kneebone Andrew , Holloway Lois
Published: March 2024

Objectives. Contouring similarity metrics are often used in studies of inter-observer variation and automatic segmentation but do not provide an assessment of clinical impact. This study focused on post-prostatectomy radiotherapy and aimed to (1) identify if there is a relationship between variations in commonly used contouring similarity metrics and resulting dosimetry and (2) identify the variation in clinical target volume (CTV) contouring that significantly impacts dosimetry. Approach. The study retrospectively analysed CT scans of 10 patients from the TROG 08.03 RAVES trial. The CTV, rectum, and bladder were contoured independently by three experienced observers. Using these contours reference simultaneous truth and performance level estimation (STAPLE) volumes were established. Additional CTVs were generated using an atlas algorithm based on a single benchmark case with 42 manual contours. Volumetric-modulated arc therapy (VMAT) treatment plans were generated for the observer, atlas, and reference volumes. The dosimetry was evaluated using radiobiological metrics. Correlations between contouring similarity and dosimetry metrics were calculated using Spearman coefficient (Γ). To access impact of variations in planning target volume (PTV) margin, the STAPLE PTV was uniformly contracted and expanded, with plans created for each PTV volume. STAPLE dose-volume histograms (DVHs) were exported for plans generated based on the contracted/expanded volumes, and dose-volume metrics assessed. Main
results. The study found no strong correlations between the considered similarity metrics and modelled outcomes. Moderate correlations (0.5 <

Γ

< 0.7) were observed for Dice similarity coefficient, Jaccard, and mean distance to agreement metrics and rectum toxicities. The observations of this study indicate a tendency for variations in CTV contraction/expansion below 5 mm to result in minor dosimetric impacts. Significance. Contouring similarity metrics must be used with caution when interpreting them as indicators of treatment plan variation. For post-prostatectomy VMAT patients, this work showed variations in contours with an expansion/contraction of less than 5 mm did not lead to notable dosimetric differences, this should be explored in a larger dataset to assess generalisability.
Edge-illumination spectral phase-contrast tomography
Authors: Brombal Luca , Arfelli Fulvia , Brun Francesco , Di Trapani Vittorio , Endrizzi Marco , Menk Ralf H , Perion Paola , Rigon Luigi , Saccomano Mara , Tromba Giuliana , Olivo Alessandro
Published: March 2024

Following the rapid, but independent, diffusion of x-ray spectral and phase-contrast systems, this work demonstrates the first combination of spectral and phase-contrast computed tomography (CT) obtained by using the edge-illumination technique and a CdTe small-pixel (62 μm) spectral detector. A theoretical model is introduced, starting from a standard attenuation-based spectral decomposition and leading to spectral phase-contrast material decomposition. Each step of the model is followed by quantification of accuracy and sensitivity on experimental data of a test phantom containing different solutions with known concentrations. An example of a micro CT application (20 μm voxel size) on an iodine-perfused ex vivo murine model is reported. The work demonstrates that spectral-phase contrast combines the advantages of spectral imaging, i.e. high-Z material discrimination capability, and phase-contrast imaging, i.e. soft tissue sensitivity, yielding simultaneously mass density maps of water, calcium, and iodine with an accuracy of 1.1%, 3.5%, and 1.9% (root mean square errors), respectively. Results also show a 9-fold increase in the signal-to-noise ratio of the water channel when compared to standard spectral decomposition. The application to the murine model revealed the potential of the technique in the simultaneous 3D visualization of soft tissue, bone, and vasculature. While being implemented by using a broad spectrum (pink beam) at a synchrotron radiation facility (Elettra, Trieste, Italy), the proposed experimental setup can be readily translated to compact laboratory systems including conventional x-ray tubes.
Benchmarking proton RBE models
Authors: Gardner Lydia L , O’Connor John D , McMahon Stephen J
Published: March 2024

Objective. To biologically optimise proton therapy, models which can accurately predict variations in proton relative biological effectiveness (RBE) are essential. Current phenomenological models show large disagreements in RBE predictions, due to different model assumptions and differences in the data to which they were fit. In this work, thirteen RBE models were benchmarked against a comprehensive proton RBE dataset to evaluate predictions when all models are fit using the same data and fitting techniques, and to assess the statistical robustness of the models. Approach. Model performance was initially evaluated by fitting to the full dataset, and then a cross-validation approach was applied to assess model generalisability and robustness. The impact of weighting the fit and the choice of biological endpoint (either single or multiple survival levels) was also evaluated. Main results. Fitting the models to a common dataset reduced differences between their predictions, however significant disagreements remained due to different underlying assumptions. All models performed poorly under cross-validation in the weighted fits, suggesting that some uncertainties on the experimental data were significantly underestimated, resulting in over-fitting and poor performance on unseen data. The simplest model, which depends linearly on the LET but has no tissue or dose dependence, performed best for a single survival level. However, when fitting to multiple survival levels simultaneously, more complex models with tissue dependence performed better. All models had significant residual uncertainty in their predictions compared to experimental data. Significance. This analysis highlights that poor quality of error estimation on the dose response parameters introduces substantial uncertainty in model fitting. The significant residual error present in all approaches illustrates the challenges inherent in fitting to large, heterogeneous datasets and the importance of robust statistical validation of RBE models.
The GaN trench MOSFET with adaptive voltage tolerance achieved through a dual-shielding structure
Authors: Qiu Yihang , Wei Li
Published: March 2024

A novel GaN trench gate vertical MOSFET (PSGT-MOSFET) with a double-shield structure composed of a separated gate (SG) and a p-type shielding layer (P_shield) is proposed and investigated. The P_shield is positioned within the drift region, which can suppress the electric field peak at the bottom of the trench during the off state. This helps to prevent premature breakdown of the gate oxide layer. Additionally, the presence of P_shield enables the device to have adaptive voltage withstand characteristics. The SG can convert a portion of gate-to-drain capacitance (C
gd) into drain-to-source capacitance (C
ds), significantly reducing the gate-to-drain charge of the device. This improvement in charge distribution helps enhance the switching characteristics of the device. Later, the impact of the position and length of the P_shield on the breakdown voltage (BV) and specific on-resistance (R
on_sp) was studied. The influence of the position and length of the SG on gate charge (Q
gd) and BV was also investigated. Through TCAD simulations, the parameters of P_shield and SG were optimized. Compared to conventional GaN TG-MOSFET with the same structural parameters, the gate charge was reduced by 88%. In addition, this paper also discusses the principle of adaptive voltage withstand in PSGT-MOSFET.
Performance degradation due to thermal cycling in soldered Faraday and SuperPower HTS tape stacks
Authors: Mouratidis Theodore , Whyte Dennis G
Published: March 2024

Soldering stacks of high temperature superconducting (HTS) tapes results in a current carrying matrix with high electrical, thermal, and mechanical stability. In some applications, these tape stacks may be exposed to elevated temperatures during thermal heat cycles. Previous research on thermal degradation of high temperature superconductors has been performed with isolated crystals or individual HTS tapes, showing that oxygen-out diffusion from the rare-earth barium copper oxide (REBCO) results in a reduction of the superconducting performance. In this work, the performance of

Pb

37

Sn

63

soldered HTS tape stacks with thermal cycling to

170

∘

C is quantified through determination of the critical current Ic
, the n-value, the linear resistance R in the pre-transition region of the tape stack current–voltage (I–V) traces, and the diffusion coefficient D associated with oxygen-out diffusion. The effect of tape manufacturer and nickel electroplating were considered; three soldered stacks each of unplated Faraday, nickel electroplated Faraday, unplated SuperPower, and nickel electroplated SuperPower tapes were fabricated. Across 20–30 one hour thermal cycles, there are no significant differences in degradation profiles observed between the unplated and nickel electroplated tape stacks for a given manufacturer. There is however a marked difference in degradation profiles observed between the SuperPower and Faraday tape stacks. For the unplated and plated SuperPower tape stacks, the degradation in Ic
generally follows the model to describe oxygen-out diffusion from the superconducting REBCO layer. Significantly less degradation is observed in the unplated and plated Faraday tape stacks, and in some sections Ic
even increases slightly across cycles. Further, cases of increasing Ic
accompanied with decreasing n are observed, a decoupling between the two parameters. Across all samples, the linear resistance was highest in current-redistribution regions near the leads. Consistent with the model of oxygen-out diffusion and the formation of an increasingly wide oxygen deficient layer in the REBCO, the linear resistance increased with cycle number.
Cavity magnomechanics: from classical to quantum
Authors: Zuo Xuan , Fan Zhi-Yuan , Qian Hang , Ding Ming-Song , Tan Huatang , Xiong Hao , Li Jie
Published: March 2024

Hybrid quantum systems based on magnons in magnetic materials have made significant progress in the past decade. They are built based on the couplings of magnons with microwave photons, optical photons, vibration phonons, and superconducting qubits. In particular, the interactions among magnons, microwave cavity photons, and vibration phonons form the system of cavity magnomechanics (CMM), which lies in the interdisciplinary field of cavity QED, magnonics, quantum optics, and quantum information. Here, we review the experimental and theoretical progress of this emerging field. We first introduce the underlying theories of the magnomechanical coupling, and then some representative classical phenomena that have been experimentally observed, including magnomechanically induced transparency, magnomechanical dynamical backaction, magnon-phonon cross-Kerr nonlinearity, etc. We also discuss a number of theoretical proposals, which show the potential of the CMM system for preparing different kinds of quantum states of magnons, phonons, and photons, and hybrid systems combining magnomechanics and optomechanics and relevant quantum protocols based on them. Finally, we summarize this review and provide an outlook for the future research directions in this field.
Theoretical prediction (DFT) and experimental observation of electronic and electro-optical properties of HATn (n = 5,6,7,8) molecules for optoelectronic applications
Authors: Mishra Mirtunjai , Pal Bhavna , Shah Asmita , Singh Dharmendra Pratap , Singh Devendra , Kumar Devesh
Published: March 2024

The formation of triphenylene core-based discotic mesogens exhibiting a classical columnar phase led to several superior electronic and optoelectronic applications. The present work reports the theoretical investigation of discotic hexaalkoxytriphenylene (HATn; n = 5, 6, 7, 8) mesogens including electro-optical, electronic, and thermodynamic properties using density functional theory (DFT) as a computational quantum mechanical tool. The various physical and chemical properties of these mesogens, such as electronegativity, specific heat capacity, polarizability, absorption, and dipole moment are calculated computationally and discussed in the study. The simulation study reveals the variation in physical properties either follows the odd–even effect or changes monotonically for HATn series. Experiment has been performed for comparison with the theoretical results. The physical and chemical properties of these discotic mesogens change with alkyl chain length variation and explain the structure–property correlation in the molecules. The obtained results of the designed molecular structure held promising applications for optoelectronic devices based on discotic mesogens.
The effect of time and heat exposure on the wettability and glossiness of CAA and FPL coatings for aluminum substrates
Authors: Nasresfahani Mohamad Reza , Asghari Saeed , Mirahmadi Seyed Javid , Gorabi Hadi
Published: March 2024

The use of anodized coatings as a substrate for adhesive bonding of aluminum is widespread and generally accepted. However, with time and exposure to heat, the coating’s behavior changes and its wettability decrease. We examine the coating’s wettability by measuring the contact angle. Aluminum sheets are coated with two types of anodizing and FPL coatings for this study. The results indicate that the wettability of all coatings remains stable for 16 h post application. However, there is a significant decrease in wettability over extended time periods, with the anodized coating exhibiting more pronounced changes after 30 days compared to the FPL coating. Also, in both types of coatings, as the heating temperature increases, the wettability decreases and the contact angle increases. The changes in the anodized coatings are more pronounced than in FPL coatings. Measuring the glossiness of the coating before and after heating shows that the gloss and the surface roughness of the coating remain unchanged.
Improved energy storage properties through multilayer stacking of relaxor ferroelectric and antiferroelectric thin films
Authors: Balaraman Anina Anju , A Antony Jeyaseelan , Dutta Soma
Published: March 2024

Multilayers of relaxor ferroelectric (Pb0.92La0.08Zr0.52Ti0.48O3) and antiferroelectric (Pb0.96La0.04Zr0.98Ti0.02O3) thin films were fabricated on Pt/Ti/SiO2/Si substrates by Chemical Solution Deposition (CSD) method. The properties of the independent relaxor ferroelectric (RFE denoted as R) and antiferroelectric (AFE denoted as A) thin films were compared with their various stack configurations made by alternatively coating the R and A layers in the patterns of R/A, R/A/R, R/A/R/A/R/A, A/R, A/R/A, and A/R/A/R/A/R. The crystallographic studies confirmed the coexistence of both RFE and AFE phases in the multilayer stacks which was further verified by electrical characterizations. The multilayer stack showed improved power density (PD), energy efficiency (η), and reduced dielectric loss compared to individual R and A films. Among all the multilayer configurations, the stack with A/R/A/R/A/R layer exhibited significant improvement in energy efficiency (94%) which is higher than the reported results so far on multilayer structures.
Control of a quadrotor on a mobile device using machine learning-based monocular gaze tracking
Authors: Hu Jiahui , Lu Yonghua , Xu Jiajun , Zhou Lihua , Feng Qiang
Published: March 2024

A machine learning-based monocular gaze tracking method for mobile devices is proposed. A non-invasive, convenient, and low-cost gaze tracking framework is developed using our constructed convolutional neural network. This framework is applied to the 3D motion control of quadrotors, which can convert the operator’s gaze attention into control intention for the quadrotor, thus allowing the operator to control the quadrotor to complete flight tasks through visual interaction. Extensive challenging indoor and outdoor real-world experiments and benchmark comparisons validate that the proposed system is robust and effective, even for unskilled operators. The proposed method can improve the smoothness and reasonableness of the motion trajectory of the quadrotor, make it more consistent with the operator’s control intention, and introduce diversity, convenience, and intuition into the control of the quadrotor. We released the source code3

3

https://github.com/hujavahui/Gaze_MAV

of our system to benefit related research.
A low-profile coding metasurface for broadband radar cross section reduction via beam diffusion and absorption
Authors: Zhou Xiaofeng , Yang Helin , Jin Jing , Guo Linyan , Li Yujun , Cheng Houyuan , Fu Yang , Dai Yilin
Published: March 2024

A low-profile coding metasurface based on beam diffusion and absorption is proposed, which can be applied for broadband Radar Cross section (RCS) reduction. Through inserting resistors into the polarization conversion element, the proposed unit cell can convert a portion of the electromagnetic wave to ohmic loss as well as retain polarization conversion. Subsequently, the power loss and surface current were used to explain the mechanism of absorption and polarization conversion, and the arrangement of the elements was optimized using a simulated annealing algorithm. Furthermore, both the simulated and measured results have shown that the RCS reduction is greater than 10 dB at 6.7–19.3 GHz (the relative bandwidth is 96.9%), and the metasurface still maintains great characteristics at 45° incidence. Thanks to the proposed metasurface offer advantages such as fewer resistors, a wider bandwidth for RCS reduction, an ultra-thin profile (0.066

λ

L

,

where

λ

L

represents the longest wavelength), a stable incident angle, and a more uniform scattering of energy, it can be used in electromagnetic stealth for large targets.
A discrete probabilistic model yielding multidimensional q − Gaussians in the thermodynamic limit for specific parameter values
Authors: Rodríguez A
Published: March 2024

We show that the N → ∞ limiting probability distributions (with N being the number of random variables to be summed) of a particular case belonging to a family of d − dimensional scale-invariant probabilistic models based on Leibniz-like (d + 1) − dimensional hyperpyramids (introduced in Rodríguez and Tsallis, J. Math. Phys 2012) are given, after an appropriate change o variables, by d − dimensional q − Gaussian distributions (

f

q
,
β

(
x
)
∝

e

q

−
β

x

T

Σ

−
1

x

, with x taking values in a subset of

R

d

, q and β real parameters, Σ a positive definite matrix, and

e

q

x

=
[
1
+
1
(
1
−
q
)
x

]

+

1

1
−
q

, with

[
u
]

+

=
max
{
u
,
0
}

), for the particular parameter values q = 3 and β < 0. Some features of these distributions, which arise in the context of Nonextensive Statistical Mechanics, as well as a connection between Dirichlet distributions and q − Gaussian distributions, which generalizes the one given for dimension 1 by Rodríguez et al, are also exposed.
Some more variety of analytical solutions to (2+1)-Bogoyavlensky-Konopelchenko equation
Authors: Kumar Raj , Pandey Kripa Shankar , Yadav Shiv Kumar , Kumar Avneesh
Published: March 2024

The goal of this study is to get analytical solutions to the Bogoyavlensky-Konopelchenko equation, which describes an interaction of a long-wavelength wave moving along the x-axis and a Riemann wave-form moving along the y-axis. The equation has been widely used in soliton theory, fluid dynamics, optics, biological systems, and differential geometry. It is a member of the Ablowitz-Kaup-Newell-Segur hierarchy of integrable systems. By exploiting the classical Lie symmetry approach, the equation is reduced to an ordinary differential equation. After solving the second similarity reduction, the authors derived a novel class of solutions for each case. Additionally, the derived solutions comprise some parameters, and various functions might be utilized to explore wave profiles like stationary, dark, and bright soliton, parabolic dark and bright soliton, and progressive nature. Solutions are compared with previous researches [18–25] to show novelty of results. Solutions can help with numerous applications in physics, such as fluid dynamics, plasma physics, and nonlinear optics.
Using a coupled optical and electrical monitoring method to follow the R-HiPIMS TiO2 deposition process drifts
Authors: Boivin D , Jean-Marie-Désirée R , Najah A , Cuynet S , de Poucques L
Published: March 2024

In this work, coupled optical and electrical discharge measurements have been implemented to investigate the plasma state of a reactive HiPIMS TiO2 deposition process running at a fixed duty cycle of 2% and at a repetition rate of 1 kHz. Investigations focus on both the effect of the erosion target and substrate-holder temperature in an Ar/O2 gas mixture at fixed working pressure. First, as the racetrack shape evolves with the use of the target, the deposition rate is modified, in the same way as the emission intensity measured. Second, with the heater set at 400 °C in pure Ar, the coating appears thinner, and the optical emission spectroscopy measurement reveals the presence of oxygen atoms. Thus, the results from the coupled optical and electrical measurements are sensitive enough to track potential drift of the process.
Artificial intelligence and feature based transfer learning framework for diagnosis of chest diseases using radiology images
Authors: Al-Otaibi Shaha , Rehman Amjad , Mujahid Muhammad , Alotaibi Sarah , Saba Tanzila
Published: March 2024

The subject of artificial intelligence-assisted diagnosis and design in the medical industry is very exciting due to considerable developments in medical imaging. In real-world applications, previous manual feature extraction strategies were inefficient in achieving the required results. The number of medical image databases is quickly increasing to accommodate hospital-based diseases as a result of the numerous uses of medical images in healthcare facilities, pathology, and medical diagnostic fields. The primary objective of this study is to create a computerized Artificial intelligence system that can accurately diagnose different diseases and reduce mistakes in the testing process. The study has two primary aspects. In the initial phase, we utilized the deep transfer learning method to extract the pertinent and crucial features from the image x-ray. Subsequently, the support vector machine employs these crucial extracted features to diagnose diseases from the x-ray14 dataset. The imbalanced dataset problem was also addressed with the utilization of the Synthetic Minority Oversampling Technique (SMOTE). The authors conduct a comparative analysis of the findings from this study in relation to other cutting-edge studies and employ cross-dataset experiments to evaluate its efficacy. The results demonstrate that the proposed approach has a detection accuracy of 95.2% for the disease. The VGG-16 model achieved 78.4% accuracy and an AUC of 90%. The proposed model can be applied to other diseases for further experiments.