bluuebunny/crossref_metadata_2025 huggingface dataset:
Coherent potential approximation study of impurity effect on monolayer hexagonal boron phosphide
Authors: Xu Jinrong , Liu Wenjing , Jiang Xiucai , Huang Kai , Li Ping , Yu Jiangying , You Yuwei , Wang Ying , Zhang Yuzhong
Published: April 2024

Impurity doping is a necessary technology for the application of semiconductor materials in microelectronic devices. The quantification of doping effects is crucial for controlling the transport properties of semiconductors. Here, taking two-dimensional (2D) hexagonal boron phosphide semiconductor as an example, we employ coherent potential approximation method to investigate the electronic properties of 2D semiconductor materials at low doping concentrations, which cannot be exploited with conventional density function theory. The results demonstrate that the positive or negative impurity potential in 2D semiconductors determines whether it is p-type or n-type doping, while the impurity potential strength decides whether it is shallow-level or deep-level doping. Impurity concentration has important impacts on not only the intensity but also the broadening of impurity peak in band gap. Importantly, we provide the operating temperature range of hexagonal boron phosphide as a semiconductor device under different impurity concentrations and impurity potentials. The methodology of this study can be applied to other 2D semiconductors, which is of great significance for quantitative research on the application of 2D semiconductors for electronic devices.
Is Ba3In2O6 a high-Tc
superconductor?
Authors: Hensling F V E , Dahliah D , Smeaton M A , Shrestha B , Show V , Parzyck C T , Hennighausen C , Kotsonis G N , Rignanese G-M , Barone M R , Subedi I , Disa A S , Shen K M , Faeth B D , Bollinger A T , Božović I , Podraza N J , Kourkoutis L F , Hautier G , Schlom D G
Published: April 2024

It has been suggested that Ba3In2O6 might be a high-Tc
superconductor. Experimental investigation of the properties of Ba3In2O6 was long inhibited by its instability in air. Recently epitaxial Ba3In2O6 with a protective capping layer was demonstrated, which finally allows its electronic characterization. The optical bandgap of Ba3In2O6 is determined to be 2.99 eV in-the (001) plane and 2.83 eV along the c-axis direction by spectroscopic ellipsometry. First-principles calculations were carried out, yielding a result in good agreement with the experimental value. Various dopants were explored to induce (super-)conductivity in this otherwise insulating material. Neither A- nor B-site doping proved successful. The underlying reason is predominately the formation of oxygen interstitials as revealed by scanning transmission electron microscopy and first-principles calculations. Additional efforts to induce superconductivity were investigated, including surface alkali doping, optical pumping, and hydrogen reduction. To probe liquid-ion gating, Ba3In2O6 was successfully grown epitaxially on an epitaxial SrRuO3 bottom electrode. So far none of these efforts induced superconductivity in Ba3In2O6, leaving the answer to the initial question of whether Ba3In2O6 is a high-Tc
superconductor to be ‘no’ thus far.
A measurement method of in-bore projectile motion acceleration based on bottom pressure correction
Authors: Zhang Yongjian , Peng Peng , Liu Tiantian , Li Dahai , Di Changan
Published: April 2024

Due to factors such as high temperatures, elevated pressures, and severe high-frequency shocks in the bore, there is considerable noise interference in acceleration test signals. This makes it challenging to accurately measure projectile motion acceleration using existing methods. To address this issue, we propose an advanced measurement approach that uses bottom pressure correction. Our model suggests a significant correlation between projectile motion acceleration and thrust. By utilizing the correlations between bottom pressure and motion acceleration in both temporal and frequency domains, we can improve the accuracy of acceleration measurements. Based on these insights, we have developed a novel testing system that synchronously measures bottom pressure and acceleration, using bottom pressure as a corrective mechanism for the measured acceleration signals. Empirical results show that the maximum relative error in peak motion acceleration is only 4.86%, demonstrating the effectiveness of our proposed method.
Meeting the detector challenges for pre-clinical proton and ion computed tomography
Authors: Johnson Robert P
Published: April 2024

Six decades after its conception, proton computed tomography (pCT) and proton radiography have yet to be used in medical clinics. However, good progress has been made on relevant detector technologies in the past two decades, and a few prototype pCT systems now exist that approach the performance needed for a clinical device. The tracking and energy-measurement technologies in common use are described, as are the few pCT scanners that are in routine operation at this time. Most of these devices still look like detector R&D efforts as opposed to medical devices, are difficult to use, are at least a factor of five slower than desired for clinical use, and are too small to image many parts of the human body. Recommendations are made for what to consider when engineering a pre-clinical pCT scanner that is designed to meet clinical needs in terms of performance, cost, and ease of use.
An end-to-end multi-scale airway segmentation framework based on pulmonary CT image
Authors: Yuan Ye , Tan Wenjun , Xu Lisheng , Bao Nan , Zhu Quan , Wang Zhe , Wang Ruoyu
Published: April 2024

Objective. Automatic and accurate airway segmentation is necessary for lung disease diagnosis. The complex tree-like structures leads to gaps in the different generations of the airway tree, and thus airway segmentation is also considered to be a multi-scale problem. In recent years, convolutional neural networks have facilitated the development of medical image segmentation. In particular, 2D CNNs and 3D CNNs can extract different scale features. Hence, we propose a two-stage and 2D + 3D framework for multi-scale airway tree segmentation.Approach. In stage 1, we use a 2D full airway SegNet(2D FA-SegNet) to segment the complete airway tree. Multi-scale atros spatial pyramid and Atros Residual Skip connection modules are inserted to extract different scales feature. We designed a hard sample selection strategy to increase the proportion of intrapulmonary airway samples in stage 2. 3D airway RefineNet (3D ARNet) as stage 2 takes the results of stage 1 asa prioriinformation. Spatial information extracted by 3D convolutional kernel compensates for the loss of in 2D FA-SegNet. Furthermore, we added false positive losses and false negative losses to improve the segmentation performance of airway branches within the lungs.Main results. We performed data enhancement on the publicly available dataset of ISICDM 2020 Challenge 3, and on which evaluated our method. Comprehensive experiments show that the proposed method has the highest dice similarity coefficient (DSC) of 0.931, and IoU of 0.871 for the whole airway tree and DSC of 0.699, and IoU of 0.543 for the intrapulmonary bronchi tree. In addition, 3D ARNet proposed in this paper cascaded with other state-of-the-art methods to increase detected tree length rate by up to 46.33% and detected tree branch rate by up to 42.97%.Significance. The quantitative and qualitative evaluation results show that our proposed method performs well in segmenting the airway at different scales.
GMAlignNet: multi-scale lightweight brain tumor image segmentation with enhanced semantic information consistency
Authors: Song Jianli , Lu Xiaoqi , Gu Yu
Published: April 2024

Although the U-shaped architecture, represented by UNet, has become a major network model for brain tumor segmentation, the repeated convolution and sampling operations can easily lead to the loss of crucial information. Additionally, directly fusing features from different levels without distinction can easily result in feature misalignment, affecting segmentation accuracy. On the other hand, traditional convolutional blocks used for feature extraction cannot capture the abundant multi-scale information present in brain tumor images. This paper proposes a multi-scale feature-aligned segmentation model called GMAlignNet that fully utilizes Ghost convolution to solve these problems. Ghost hierarchical decoupled fusion unit and Ghost hierarchical decoupled unit are used instead of standard convolutions in the encoding and decoding paths. This transformation replaces the holistic learning of volume structures by traditional convolutional blocks with multi-level learning on a specific view, facilitating the acquisition of abundant multi-scale contextual information through low-cost operations. Furthermore, a feature alignment unit is proposed that can utilize semantic information flow to guide the recovery of upsampled features. It performs pixel-level semantic information correction on misaligned features due to feature fusion. The proposed method is also employed to optimize three classic networks, namely DMFNet, HDCNet, and 3D UNet, demonstrating its effectiveness in automatic brain tumor segmentation. The proposed network model was applied to the BraTS 2018 dataset, and the results indicate that the proposed GMAlignNet achieved Dice coefficients of 81.65%, 90.07%, and 85.16% for enhancing tumor, whole tumor, and tumor core segmentation, respectively. Moreover, with only 0.29 M parameters and 26.88G FLOPs, it demonstrates better potential in terms of computational efficiency and possesses the advantages of lightweight. Extensive experiments on the BraTS 2018, BraTS 2019, and BraTS 2020 datasets suggest that the proposed model exhibits better potential in handling edge details and contour recognition.
Probabilistic U-Net model observer for the DDC method in CT scan protocol optimization
Authors: Stocker David , Sommer Christian , Gueng Sarah , Stäuble Jason , Özden Ismail , Griessinger Jennifer , Weyland Mathias S , Lutters Gerd , Scheidegger Stephan
Published: April 2024

Optimizing complex imaging procedures within Computed Tomography, considering both dose and image quality, presents significant challenges amidst rapid technological advancements and the adoption of machine learning (ML) methods. A crucial metric in this context is the Difference-Detailed Curve, which relies on human observer studies. However, these studies are labor-intensive and prone to both inter- and intra-observer variability. To tackle these issues, a ML-based model observer utilizing the U-Net architecture and a Bayesian methodology is proposed. In order to train a model observer unaffected by the spatial arrangement of low-contrast objects, the image preprocessing incorporates a Gaussian Process-based noise model. Additionally, gradient-weighted class activation mapping is utilized to gain insights into the model observer’s decision-making process. By training on data from a diverse group of observers, well-calibrated probabilistic predictions that quantify observer variability are achieved. Leveraging the principles of Beta regression, the Bayesian methodology is used to derive a model observer performance metric, effectively gauging the model observer’s strength in terms of an ‘effective number of observers’. Ultimately, this framework enables to predict the DDC distribution by applying thresholds to the inferred probabilities (Part of this work has been presented at: Stocker D, Sommer C, Gueng S, Stäuble J, Özden I, Griessinger J, Weyland M S, Lutters G, Scheidegger S (2023). Probabilistic U-Net Model Observer for the DDC Method in CT Scan Protocol Optimization. The 56th SSRMP Annual Meeting 2023, November 30. - December 1., 2023, Luzern, Switzerland).
TOPAS simulation of photoneutrons in radiotherapy: accuracy and speed with variance reduction
Authors: Ramos-Mendez J , Ortiz Catalan R , Schuemann J , Paganetti H , Faddegon B
Published: April 2024

Objective. We provide optimal particle split numbers for speeding up TOPAS Monte Carlo simulations of linear accelerator (linac) treatment heads while maintaining accuracy. In addition, we provide a new TOPAS physics module for simulating photoneutron production and transport. Approach. TOPAS simulation of a Siemens Oncor linac was used to determine the optimal number of splits for directional bremsstrahlung splitting as a function of the field size for 6 MV and 18 MV x-ray beams. The linac simulation was validated against published data of lateral dose profiles and percentage depth-dose curves (PDD) for the largest square field (40 cm side). In separate simulations, neutron particle split and the custom TOPAS physics module was used to generate and transport photoneutrons, called ‘TsPhotoNeutron’. Verification of accuracy was performed by comparing simulations with published measurements of: (1) neutron yields as a function of beam energy for thick targets of Al, Cu, Ta, W, Pb and concrete; and (2) photoneutron energy spectrum at 40 cm laterally from the isocenter of the Oncor linac from an 18 MV beam with closed jaws and MLC. Main results. The optimal number of splits obtained for directional bremsstrahlung splitting enhanced the computational efficiency by two orders of magnitude. The efficiency decreased with increasing beam energy and field size. Calculated lateral profiles in the central region agreed within 1 mm/2% from measured data, PDD curves within 1 mm/1%. For the TOPAS physics module, at a split number of 146, the efficiency of computing photoneutron yields was enhanced by a factor of 27.6, whereas it improved the accuracy over existing Geant4 physics modules. Significance. This work provides simulation parameters and a new TOPAS physics module to improve the efficiency and accuracy of TOPAS simulations that involve photonuclear processes occurring in high-Z materials found in linac components, patient devices, and treatment rooms, as well as to explore new therapeutic modalities such as very-high energy electron therapy.
Avalanche statistics of fluctuation-induced fluxes from the SLPM and the W7-AS stellarator
Authors: Mier J A , Blanco J , Sánchez R , Castellanos O F , Newman D E , Anabitarte E , López J M
Published: April 2024

Measurements of fluctuating floating potentials and ion saturation currents at different radial locations in the Santander Linear Plasma Machine (Castellanos et al 2005 Plasma Phys. Control. Fusion
47 2067) and at the edge of the W7-AS stellarator by means of radially movable Langmuir probes allow to infer the corresponding fluctuation-induced radial flux temporal series. Avalanche-like transport events are identified in the time series and statistically characterized in terms of avalanche size/duration/quiet-time distributions and size-duration scaling relations. Transport is diffusive in the inner and intermediate radial region of the SLPM

r
<

r
tr

≈
2.6

cm, undergoing a transition at

r
tr

, becoming non-diffusive in the outermost region of the device,

r
>

r
tr

. The results obtained at the edge of the W7-AS stellarator are similar to those found in SLPM for

r
>

r
tr

, i.e. consistent with what would be expected for scale-free, self-similar plasma transport dynamics near a critical state.
Study of the photoluminescence properties of GaN irradiated with low fluence Ta ions
Authors: Wei Wanting , Zhao Guijuan , Liu Jiande , Wang Xingliang , Liu Guipeng
Published: April 2024

The irradiation influences the properties of GaN. We studied the irradiation of n-type, p-type, and i-type GaN with 2.896 GeV Ta ions, with experimental irradiation fluence of 3 × 108, 3 × 109, and 2 × 1010 cm−2, respectively. Low fluence ion irradiation of GaN enhances the luminescence performance of the samples and releases stress between GaN and the sapphire substrate. We demonstrate by characterizing GaN that this is due to the displacement of Ga or N atoms repairing the defects caused by the entry of irradiated ions, thus enhancing the performance of GaN. This provides a reference for low fluence irradiation of GaN.
A negative capacitance field effect transistor with a modified gate stack and drain-side cavity for label-free biosensing
Authors: Kansal Harshit , Medury Aditya Sankar
Published: April 2024

Dielectrically modulated (DM) negative capacitance field effect transistor (NCFET)-based label-free biosensors have emerged as promising devices for accurate detection of various biomolecules, where the sensitivity of DM architectures strongly depends on the sensing mechanism as well as on the size of the nanocavity. Therefore, to achieve higher sensitivity along with reduced fabrication complexity, we propose to utilize a pre-existing drain-side spacer region as a nanocavity, in a fully depleted silicon-on-insulator-based NCFET architecture. The ferroelectric (FE) layer in the metal-ferroelectric-insulator-semiconductor configuration meaningfully alters the impact of the drain’s electric field on the source-side electrostatics, which results in higher sensitivity. Having quantified the sensitivity of an FE-dielectric (FE-DE) gate-stack-based NCFET biosensor, we now propose to include a paraelectric (PE) layer between the FE and DE materials, thus modifying the gate stack from FE-DE to FE-PE-DE with an equivalent negative capacitance seen from both stacks; here, a remarkable improvement is seen in the FE-PE-DE gate-stack-based NCFET, with nearly identical linearity performance, as seen from the high Pearson’s coefficient value (

r
2

⩾

0.9). Therefore, to illustrate the efficacy of the proposed sensing mechanism and the modified gate stack (FE-PE-DE), DE constant (

k

Bio

) values in the range of

k

Bio

= 4.5 to

k

Bio

= 75.99 are considered. Finally, the effect of scaling the channel length (

L

g

) on the sensitivity of the FE-PE-DE NCFET device is shown, and a high value, particularly at lower permittivity, demonstrates the versatility and wide applicability of the proposed NCFET biosensor.
Manipulating the dipolar interactions and cooperative effects in confined geometries
Authors: Alaeian Hadiseh , Skljarow Artur , Scheel Stefan , Pfau Tilman , Löw Robert
Published: April 2024

To facilitate the transition of quantum effects from the controlled laboratory environment to practical real-world applications, there is a pressing need for scalable platforms. One promising strategy involves integrating thermal vapors with nanostructures designed to manipulate atomic interactions. In this tutorial, we aim to gain deeper insights into this by examining the behavior of thermal vapors that are confined within nanocavities or waveguides and exposed to near-resonant light. We explore the interactions between atoms in confined dense thermal vapors. Our investigation reveals deviations from the predictions of continuous electrodynamics models, including density-dependent line shifts and broadening effects. In particular, our results demonstrate that by carefully controlling the saturation of single atoms and the interactions among multiple atoms using nanostructures, along with controlling the geometry of the atomic cloud, it becomes possible to manipulate the effective optical nonlinearity of the entire atomic ensemble. This capability renders the hybrid thermal atom-nanophotonic platform a distinctive and valuable one for manipulating the collective effect and achieving substantial optical nonlinearities.
Characterization of cascaded arc He plasma in a compact linear plasma device using voltammetry and optical emission spectroscopy
Authors: Wang Yong , Zhou Hai-shan , Li Xue-chun , Liu Hao-dong , Zhu Yi-wen , Luo Guang-nan
Published: April 2024

Cascaded arc plasma has been widely applied in linear plasma devices (LPDs) to produce high flux plasma for the study of plasma-material interaction. In this work, cascaded arc He plasma produced in an LPD with a compact arrangement is investigated by voltammetry and optical emission spectroscopy (OES). The results show that the cathode potential increases with the discharge current while it firstly decreases and then increases as increasing the gas flow rate. A local reverse electric field is observed at low gas flow rates between two cascaded plates (i.e. floating electrodes) near the cathode. The OES’ results reveal that as the gas flow rate increases, the intensity of He I lines increases and the electron excitation temperature (T

exc
) decreases. As increasing the discharge current, the intensity of He lines exhibits various trends at different gas flow rates, showing a monotonic decline at 1.94 slm and a first increase followed by a reduction at 3.52 slm. The T

exc
increases with the discharge current. These findings could preliminarily shed light on the properties of cascaded arc of He plasma in the compact LPD and aid in the optimization of the device to generate the high-flux divertor-relevant plasma.
Optimizing FDM process parameters: predictive insights through taguchi, regression, and neural networks
Authors: Khusheef Ahmed Shany , Hashemi Ramin , Shahbazi Mohammad
Published: April 2024

Fused deposition modelling (FDM) is a popular additive manufacturing process used for rapid prototyping and the production of complex geometries. Despite its popularity, FDM’s susceptibility to variations in numerous process parameters can significantly impact the quality, design, functionality, and mechanical properties of 3D printed parts. This study explores thirteen FDM process parameters and their influence on the mechanical properties of polylactic acid (PLA) polymer, encompassing surface roughness, warpage, tensile and bending strength, elongation at break, deformation, and microhardness. The optimum parameters were identified alongside key contributors by applying the Taguchi method, signal-to-noise ratios, and analysis of variances (ANOVA). Notably, specific FDM parameters significantly affect the surface profile, with layer thickness contributing 32.65% and fan speed contributing 8.59% to the observed variations. Similarly, warping values show notable influence from nozzle temperature (29.53%), wall thickness (16.74%), layer thickness (16.56%), and retraction distance (12.80%). Tensile strength is primarily determined by wall thickness (31.83%), followed by infill percentage (26.73%) and infill pattern (16.18%). Elongation at break predominantly correlates with wall thickness (44.82%), with a supplementary contribution from nozzle temperature (10.90%). Microhardness lacks a dominant parameter. Bending strength variations primarily arise from layer thickness (38%), wall thickness (37.6%), and infill percentage (9.17%). Deformation tendencies are influenced by layer thickness (19.20%), print speed (11.37%), wall thickness, and fan speed (10.9% each). The optimized dataset of FDM process parameters was then employed in two prediction models: multiple-regression and artificial neural network (ANN). Evaluation based on the correlation coefficient (R2) and root mean squared error (RMSE) indicates that the ANN model outperforms the multiple-regression approach. The results indicate that precise control of FDM parameters, coupled with ANN predictions, facilitates the fabrication of 3D printed parts with the desired mechanical characteristics.
Perturbative stability analysis of deformable charged bodies revealing the mathematical origin of Planck constant
Authors: Bhattacharya Sukalyan , Bhattacharya Sonal
Published: April 2024

This article considers elementary particles like electrons as finitely sized deformable bodies and analyzes the classical mechanics of their interior continuum. The consequent findings answer a long-standing question in physics by computing Planck constant mathematically. It also explains quantum phenomena like wave-particle duality, uncertainty principle and atomic stability without resorting to phenomenological relations like Planck’s law or Bohr’s postulates. The analysis introduces the criteria for perpetual stability under arbitrary perturbations to compensate for the lack of system-defining initial conditions typically available in a classical mechanics problem. Accordingly, unperturbed leading order field solutions are first constructed from steady rotation and axisymmetric electromagnetic potentials. Then, novel perturbation theories uniquely render the particulate geometry along with mass and charge distributions by exploiting the stability conditions. The approach reveals the perpetually stable body to have surface charges encapsulating a slender disk with a radius-to-thickness ratio 51.36 and a rim velocity of 0.09798c. The volumetric densities for rest-mass and charge are seen to vary with dimensionless radius (r) as

(
1
−

r

2

)

−
3

/

2

and

(
1
−

r

2

)

−
2

. The theory infers that the deformable system with many degrees of freedom would exhibit several pulsating modes. One such vibration, named quantum mode in this paper, causes spontaneous oscillation of the particulate center in the equatorial plane with a unique time period of oscillation. This wavy motion manifests wave-particle duality, whereas its probabilistic amplitude is identified as the reason behind quantum uncertainties. Moreover, in response to external fields, the charge deforms to create dipoles which can nullify radiation-inducing Poynting vector to ensure atomic stability. Finally, the Planck constant is retrieved after dividing the rest-energy by the frequency of the quantum mode. Thus, the paper concludes that a new detailed mechanics can potentially describe subatomic physics if charges are perceived as perpetually stable but readily deformable finite bodies, not rigid shape-less entities.
Exploration of the optical characteristics in sol-gel synthesized europium-doped zinc oxide thin films for potential optoelectronic use: a comprehensive characterization approach
Authors: Tahir Asma , Bujran M Ashraf , Want Basharat
Published: April 2024

In this study, we present our findings on the spin coated pure Zinc-Oxide (ZnO) nanowire arrays and Europium doped ZnO (Eu3+: ZnO) nanostructure thin films. These arrays were grown on soda lime (silica) coated glass substrate. We conducted a comprehensive analysis of the structural and optical properties of the as-synthesized nanostructures. The characterization techniques included x-ray Diffraction, FESEM Analysis, Raman Spectroscopy, Photoluminescence and UV–vis Analysis. The XRD findings indicate the incorporation of Europium (Eu3+) into the ZnO crystalline lattice, potentially replacing Zn2+ ions. This doping with Europium (Eu3+) led to a reduction in crystalline size, as determined by Scherrer’s equation decreasing from 48 nm to 28 nm demonstrates a decrease in defects within the films. Raman Shift analysis revealed changes in the optical properties of films with inclusion of Europium in host matrix. Photoluminescence studies demonstrated a distinctive 5D0 to 7F2 transition arising from the Eu3+ ions, observed at approximately 612 nm. We have thoroughly examined the optical characteristics of both Europium-doped and pure ZnO thin films through a systematic study. The optical properties were assessed by analyzing the absorption spectra (220–600 nm) and transmission spectra within the wavelength range of 200 to 1200 nm. The film exhibited an impressive 80% transparency, particularly noteworthy for window layer application. The refractive index (n), extinction coefficient (k) and all other associated parameters were found to be impacted by the doping of Europium. The refractive index dispersion relation has been explored using a single oscillator model. Furthermore, the non-linear optical susceptibility (χ
3) and non-linear refractive index were computed using semi-empirical relationships based on the linear optical parameters. The Europium (Eu3+) doping in ZnO led to an increase in the χ
3 value elevating it from 4.07 × 10–1° to 5.91 × 10–1° e.s.u. These findings suggest that Europium-doped ZnO nanostructures have the potential to be a promising platform for the development of efficient multispectral light-emitting diodes (LED’s) and optical devices.
Revisiting the energy spectrum of the radial screened Coulomb potential
Authors: Xu Lei , Fernández Francisco M , Jiao Li Guang , Montgomery Henry E , Ho Yew Kam , Fritzsche Stephan
Published: April 2024

We revisit the energy spectrum of the radial screened Coulomb potential

V
(
r
)
=
−
exp
(
−
C

/

r
)

/

r

and analyze the small- and large-parameter (C) asymptotic laws of the system eigenenergies in both the original and C-scaled Schrödinger equations. The discrepancy observed in our previous work [Xu et al (2023) Phys. Lett. A
483, 129 064] with the numerical calculations of Stachura and Hancock [(2021) J. Phys. Commun.
5, 065 004] is resolved by reinterpreting their results as the eigenenergies of two-body systems of equal mass. We derive an improved analytical expression for system energies at small values of C and an approximate asymptotic law for arbitrary l-state energies when C approaches infinity. The behavior of the scaled system energies and wave functions is analyzed in the large-parameter limit. The present study provides solid proof that the radial screened Coulomb potential supports an infinite number of bound states for finite values of screening parameter, which completes the investigation of the energy spectrum of this special potential.
Multiple scroll attractors and multistability in the collective dynamics of a four chain coupled hopfield inertial neuron network: analysis and circuit design investigations
Authors: Sogui Dongmo T N , Kengne Jacques
Published: April 2024

This work deals with the chain bidirectional coupling of four inertial Hopfield neurons. Each of our cells taken alone is modeled by a second order differential equation having three resting points. Coupling these neurons helps increasing the number of fixed points that is related to the amount of memory assigned to the network. The system having a hyperbolic tangent as nonlinearity is investigated with the help of suitable nonlinear dynamical tools like bifurcation diagrams, Lyapunov exponent diagrams and phase portraits to resort the richness of the model. As the coupling adds the amount of equilibriums, it also helps in generating multiple scroll attractors. The system that was unable of oscillation presents firing patterns such as parallel branches, coexistence of up to sixteen attractors in the phase plane, extreme events and Hopf bifurcation to name a few. All these features are discovered when observing the coupling strengths, the dissipation coefficient and when programming initial states around sensitive equilibriums. The electronic version of the four-chain coupled inertial neurons system is provided and simulated on Pspice with the aim to confirm the results obtained in the numerical scheme.
Two-term Boltzmann approximation versus Monte-Carlo simulation: effect of magnetic field
Authors: Tereshonok Dmitry , Chernyshev Timofey , Abramov Artem G , Ugryumov Aleksandr V
Published: April 2024

In this paper, we investigate the spatial-local electron energy distribution function (eEDF) interacting with a background gas at the sub-atmospheric pressure in a wide range of applied crossed electric and magnetic fields using the Boltzmann kinetic equation. We compare solutions obtained using two numerical approaches (deterministic two-term approximation and stochastic Monte Carlo method) to identify their applicability in the context of determining drift velocity and reaction constants for electrons. For argon and helium, the upper limit of the reduced electric field applicability of the two-term approximation is discussed. It has been shown that the presence of a magnetic field can reduce this limit. Two explanations are given, one is based on the math of two-term formalism, and the other is based on velocity-space analysis. Two-term approximation fails due to it’s inability to resolve underlying cyclotron oscillation (it should result in an energy variation along the electron’s trajectory). The absence of this feature causes an incorrect estimation of momentum-transfer rate. This results an inaccuracy in the estimation of the angle between electric field and drift velocity.
First-principle simulation of inorganic Na2CuSbX6 (X = Cl, Br, I) halides for photovoltaic and energy conversion applications
Authors: Nasrullah Fariha , Noor N A , Elansary Hosam O , Mumtaz Sohail
Published: April 2024

The exceptional flexibility of optoelectronic attributes exhibited by inorganic Na2CuSbX6 (X = Cl, Br, I) halides has sparked significant interest in recent research. Our approach involves the utilization of Wien2k and BoltzTrap coding to scrutinize the mechanical, thermoelectric and optoelectronic attributes of studied halides. Structural stability have been investigated through Born stability criteria employing generalized gradient approximation (GGA-PBEsol). In addition, negative formation energy (−2.15 eV for Cl-halide, −1.88 eV for Br-halide and −1.68 eV for I-halide) indicate all halides are thermo-dynamical stable. For accurate calculation of optoelectronic properties, modified Becke and Johnson (mBJ) potential has been employed. Band structure indicate all halides are semiconductor with indirect bandgap nature having bandgap values 1.7 eV for Cl-halide, 1.34 eV for Br-halide and 0.85 eV for I-halide respectively. Substituting Cl-halide with Br and I-halide results in enhanced optical absorption predominantly in the visible region, causing a shift in the absorption edge from visible light to IR. Further, electronic thermoelectric properties are discussed against temperature 300 K to 800 K. The computed higher Seebeck coefficient observed in Na2CuSbI6 suggests that a narrower band gap is more suitable for thermoelectric applications in comparison to Na2CuSbBr6 and Na2CuSbCl6. In a broader context, the computational analysis of thermoelectric and optical properties indicates that Li2CuSbX6 halides is generally well suited for use in solar cell devices and energy conversion applications.
Optimization of all-polymer/Sb2Se3 tandem solar cells for enhanced efficiency: a comprehensive TCAD modeling approach
Authors: Alanazi Tarek I , Shaker Ahmed , Gad Michael , Okil Mohamed
Published: April 2024

This paper introduces a novel tandem configuration, utilizing an all-thin film all-polymer solar cell (all-PSC) with a wide bandgap of 1.76 eV for the front cell and Sb2Se3 with a narrow bandgap of 1.2 eV for the bottom cell. The design of this tandem is performed by comprehensive optoelectronic TCAD tools, essential for optimizing parameters across multiple layers to reach maximum power conversion efficiency (PCE). Experimental validation of models is conducted through calibration and validation against fabricated reference all-polymer and Sb2Se3 solar cells, yielding calibrated PCEs of approximately 10.1% and 10.5%, respectively. Subsequently, validated simulation models for both top and rear cells are utilized to design a 2-T all-polymer/Sb2Se3 tandem cell, which initially achieves a PCE of 10.91%. Through systematic optimization steps, including interface engineering and homojunction structure design, a remarkable PCE of 24.24% is achieved at the current matching point, showcasing the potential of our proposed tandem solar cell design. This study represents a significant advancement in the field of thin-film tandem solar cells, offering promising avenues for efficient and cost-effective photovoltaic technologies, particularly in applications requiring flexibility.
Controllability of time-varying fractional dynamical systems with distributed delays in control
Authors: Vishnukumar K S , Sivalingam S M , Govindaraj V
Published: April 2024

This study examines the controllability results in the realm of Caputo fractional derivatives, focusing on time-varying linear and nonlinear fractional dynamical systems with distributed delays in control. In the setting of a linear system, using the Grammian matrix’s positive definiteness makes it possible to ascertain both the necessary and sufficient conditions. Schauder’s fixed point theorem is utilized to outline the sufficient conditions for establishing the controllability of time-varying nonlinear fractional dynamical systems. In addition to that, the paper discusses the controllability of a nonlinear integrodifferential system for a particular case. A few examples and the graphs that correspond to them are shown here to make it easier to conceptualize the conclusions of the theoretical discussion.
Induced circular polarization on photons due to interaction with axion-like particles in rotating magnetic field of neutron stars
Authors: Sharifian M. , Zarei M. , Matarrese S. , Turolla R.
Published: April 2024

We investigate how the photon polarization is affected by the interaction with axion-like particles (ALPs) in the rotating magnetic field of a neutron star (NS). Using quantum Boltzmann equations the study demonstrates that the periodic magnetic field of millisecond NSs enhances the interaction of photons with ALPs and creates a circular polarization on them. A binary system including an NS and a companion star could serve as a probe. When the NS is in front of the companion star with respect to the earth observer, there is a circular polarization on the previously linearly polarized photons as a result of the interaction with ALPs there. After a half-binary period, the companion star passes in front of the NS, and the circular polarization of photons disappears and changes to linear. The excluded parameter space for a millisecond NS with 300 Hz rotating frequency, highlights the coupling constant of 1.7 × 10-11 GeV-1 ≤ gaγγ
≤ 1.6 × 10-3 GeV-1 for the ALP masses in the range of 7 × 10-12 eV ≤ ma
≤ 1.5 × 103 eV.
DEMNUni: cross-correlating the nonlinear ISWRS effect with CMB-lensing and galaxies in the presence of massive neutrinos
Authors: Cuozzo Viviana , Carbone Carmelita , Calabrese Matteo , Carella Elisabetta , Migliaccio Marina
Published: April 2024

We present an analytical modelling of the angular cross-correlations between the Integrated Sachs Wolfe-Rees Sciama (ISWRS) effect and large-scale structure tracers in the presence of massive neutrinos. Our method has been validated against large N-body simulations with a massive neutrino particle component, namely the DEMNUni suite. We investigate the impact of different neutrino masses on the cross-correlations between the ISWRS effect and both the galaxy clustering and the lensing of the Cosmic Microwave Background (CMB). We also test the ability of current nonlinear matter power spectrum modellings to reproduce neutrino effects in such cross-correlations. We show that the multipole position of a characteristic sign inversion in the cross-spectra, due to nonlinear effects, is strongly related to the total neutrino mass Mν
and depends almost linearly on it. While these nonlinear cross-correlation signals may not be able alone to constrain the neutrino mass, our approach paves the way to the detection of such cross-spectra on small scales for their exploitation in combination with main probes from future galaxy surveys and CMB experiments.
Solar Image Quality Assessment: A Proof of Concept Using Variance of Laplacian Method and its Application to Optical Atmospheric Condition Monitoring
Authors: So Chu Wing , Yuen Edwin Lok Hei , Leung Edgar Heung Fat , Pun Jason Chun Shing
Published: April 2024

Here we present a proof of concept for the application of the Variance of Laplacian (VL) method in quantifying the sharpness of optical solar images. We conducted a comprehensive study using over 65,000 individual solar images acquired on more than 160 days. Each image underwent processing using a VL image processing algorithm, which assigns a “score” based on the sharpness of the solar disk’s edges. We studied the scores obtained from images acquired at different conditions. Our findings demonstrate that the sharpness of the images exhibits daily trends that are closely linked to the altitude of the Sun at the observation site. We observed a significant degradation in image quality only below a certain altitude threshold. Furthermore, we compared airmass formulae from the literature with our sharpness observations and concluded that the degradation could be modeled as an Image Sharpness Function (ISF), which exhibits similarities to airmass variations. In addition to assessing image quality, our method has the potential to evaluate the optical atmospheric conditions during daytime observations. Moreover, this technique can be easily and cost-effectively applied to archival or real-time images of other celestial bodies, such as the Moon, bright planets and defocused stars. Given that ISF is unique to each location and sensitive to sky conditions, the development of an ISF is not only beneficial for routine observation preparation but also essential for long-term site monitoring.
Restoring cosmological concordance with axion-like early dark energy and dark matter characterized by a constant equation of state?
Authors: Yao Yan-Hong , Meng Xin-He
Published: April 2024

The Hubble tension persists as a challenge in cosmology. Even early dark energy (EDE) models, initially considered the most promising for alleviating the Hubble tension, fall short of addressing the issue without exacerbating other tensions, such as the S
8 tension. Considering that a negative dark matter (DM) equation of state (EoS) parameter is conducive to reduce the value of the σ
8 parameter, we extend the axion-like EDE model in this paper by replacing the cold dark matter (CDM) with DM characterized by a constant EoS w
dm (referred to as WDM hereafter). We then impose constraints on this axion-like EDE extension model, along with three other models: the axion-like EDE model, ΛWDM, and ΛCDM. These constraints are derived from a comprehensive analysis incorporating data from the Planck 2018 cosmic microwave background, baryon acoustic oscillations, and the Pantheon compilation, as well as a prior on H
0 (i.e. H
0 = 73.04 ± 1.04, based on the latest local measurement by Riess et al) and a Gaussianized prior on S
8 (i.e. S
8 = 0.766 ± 0.017, determined through the joint analysis of KID1000+BOSS+2dLenS). We find that although the new model maintains the ability to alleviate the Hubble tension to ∼1.4σ, it still exacerbates the S
8 tension to a level similar to that of the axion-like EDE model.
95 GeV light Higgs in the top-pair-associated diphoton channel at the LHC in the minimal dilaton model*
Authors: Wang 王 Kun 坤 , Zhu 朱 Jingya 经亚
Published: April 2024

Motivated by experimental hints and theoretical frameworks indicating the existence of an extended Higgs sector, we explore the feasibility of detecting a 95 GeV light Higgs boson decaying into a diphoton within the minimal dilaton model at the 14 TeV LHC. Initially, we identify the correlations between the production cross section, decay branching ratios, and model parameters, e.g., the scalar mixing angle

. Subsequently, we utilize Monte Carlo simulations to generate the signal of the light Higgs boson via the

process, along with the corresponding backgrounds. To effectively separate the signal from the dominant backgrounds

, we employ a meticulous cut-based selection process. Ultimately, we find that with an integrated luminosity of

, the regions of

can be covered over the

level.
A discrete time crystal order in the driven Ising model: thermal effects, jamming analogy and quench dynamics
Authors: Jeong Kangeun , Kim Bongsoo , Jong Lee Sung
Published: April 2024

We explore the emergence of a discrete time crystalline (DTC) order and its stability against thermal fluctuations in a driven kinetic Ising model on a two-dimensional square lattice using the drive protocol invented in a recent work (Gambetta et al 2019 Phys. Rev. E 100 060105(R)). The DTC order is found to be quite robust in the presence of thermal fluctuations. We construct the resulting three-dimensional phase diagram for the DTC order, which manifests a striking resemblance to the jamming phase diagram proposed by Liu and Nagel. This finding may suggest a new way to view the DTC order as a new type of nonequilibrium soft matter. The quench dynamics exhibits a unique feature due to the nature of the employed drive protocol, namely, breakdown of the inverse relationship between the domain growth and defect relaxation, which holds in the usual quench dynamics of the kinetic Ising model.
A prototype Radiation Energy Measuring Integrated Circuit with an asynchronous current-pulse reset block providing analog-to-digital conversion in 28 nm CMOS
Authors: Kaczmarczyk Piotr , Kmon Piotr
Published: April 2024

In this paper we introduce a prototype Radiation Energy Measuring Integrated Circuit (REMIC) fabricated in a 28 nm CMOS process. The chip operates in a single-photon counting (SPC) mode and contains 100 pixels with a size of 50 μm × 50 μm. It is designed for precise energy measurements using asynchronous analogue-to-digital conversion. The proposed architecture allows both fast signal processing and precise energy measurement of incoming photons to be performed independently in each pixel, occupying a small pixel area. The integrated circuit (IC) has dimensions of 1.1 mm × 1.1 mm and is currently undergoing preliminary measurements. The paper focuses on the methodology used to mitigate process variations in each of the recording channels.
Simulation of a semiconductor voxelized helmet brain PET scanner
Authors: Kolstein Machiel , Chmeissani Mokhtar , Saini Divya , Miramón Juan Carlos Martín
Published: April 2024

Alzheimer's disease (AD) is a mental deterioration that severely impacts memory, disrupts brain functionality and induces physical changes to the brain.
It is at present an incurable disease but a timely diagnosis of AD can help to slow down its progression.
Invasive methods to collect cerebrospinal fluid (CSF) biomarkers are increasingly being used for the diagnosis of AD.
Alternatively, because of the growing effort in trying to detect the early markers of AD,
nowadays there are many neuroimaging projects developing
non-invasive dedicated brain positron emission tomography (PET) scanners with a helmet shape.
In this work, a helmet shaped brain PET is proposed with high spatial and energy resolutions, which could play a vital role in the early diagnosis of AD.
It consists of highly 3D segmented detector modules with a density of more than 350 channels/cm3 and a seamless geometry based on trapezoidal-shaped modules equipped with semiconductor CdTe detectors.
The proposed helmet brain PET scanner has an axial field-of-view (FOV) of 154 mm, and inner and outer radii of 133 mm and 206 mm respectively.
Its performance has been evaluated via simulations based on NEMA protocols and compared to other brain PET scanners.
Additionally, brain PET/CT images in DICOM format were used for a more realistic and stringent test of the imaging quality of the proposed PET scanner and the reconstruction of regional FDG uptakes.
Results are presented that show that the proposed PET scanner
can detect deviations in uptake of 2% or larger from a reference image.
Study of polysterene based scintillator ageing in the DANSS experiment
Authors: Alekseev I. , Belov V. , Bystryakov A. , Danilov M. , Filosofov D. , Fomina M. , Gorovtsov P. , Iusko Ye. , Kazartsev S. , Kobyakin A. , Krapiva A. , Kuznetsov A. , Mashin N. , Machikhiliyan I. , Medvedev D. , Nesterov V. , Ponomarev D. , Rozova I. , Rumyantseva N. , Rusinov V. , Salamatin A. , Samigullin E. , Shevchik Ye. , Shirchenko M. , Shitov Yu. , Skrobova N. , Svirida D. , Tarkovsky E. , Yakovleva A. , Yakushev E. , Zhitnikov I. , Zinatulina D.
Published: April 2024

DANSS is a spectrometer for reactor antineutrinos based on
plastic scintillator. The sensitive volume of the detector is made
of 2500 polystyrene based scintillator plates with wavelength
shifting (WLS) fiber readout (strips). We present a study of the
light yield of strips during 6.5 years of DANSS continuous
running. Overall ageing at the rate
0.55 ± 0.05 (syst.) % per year is observed that is
considerably smaller than in other similar experiments. We also
observe the WLS fiber attenuation length shortening at the rate
0.26 ± 0.04(stat.) % per year.