bluuebunny/crossref_metadata_2025_split huggingface dataset:
Huge photosensitivity gain combined with long photocurrent decay times in various polymorphs of Ga2O3: effects of carrier trapping with deep centers
Authors: Polyakov A Y , Yakimov E B , Shchemerov I V , Vasilev A A , Kochkova A I , Nikolaev V I , Pearton S J 
Published: November 2024

Abstract
The material system of ultra-wide bandgap Ga2O3 has already shown great promise in the field of solar-blind photodetectors with high photoresponsivity, high photoresponsivity gain and low dark current. These promising results have been achieved on Ga2O3 films of different polymorphs and by different methods, often not with particularly high crystalline quality. In fact, it would often seem the case that the lower the crystalline quality of the films, the higher the photosensitivity and its gain. This, however, is in most cases accompanied by unusually long photocurrent build-up and decay times. We show that the experimental results can be explained by models in which the high photosensitivity gain is related to the effects of holes being trapped by deep states, which, in Schottky diodes, results in a decrease of the Schottky barrier height with a consequent increase in the electron current, and in metal–semiconductor–metal (MSM) structures additionally gives rise to the usual gain increase due to the increased concentration and lifetime of electrons. We present and discuss models describing the effects in Ga2O3 Schottky diodes, MSM structures, and unipolar and bipolar heterojunctions, and we propose possible candidates for the role of the hole traps in different Ga2O3 polymorphs. We also discuss the existing results for the photocurrent build-up and decay times and offer possible explanations for the observed temperature dependences of the characteristic times where such data are present.
Programmable metasurface based phase-modulating reflector for 2.4 GHz wireless communications
Authors: Chu Wei , Cao Wei , Zhang Qiong , Gao Mandi , Ren Xiaole , Ji Zhonghang , Liu Yunqing 
Published: November 2024

Abstract
This paper presents an innovative programmable metasurface structure that achieves precise phase control within the 2–2.7 GHz frequency range by adjusting the state of varactor diodes embedded in the unit cells. The design employs a single diode, which simplifies the structure, reduces manufacturing costs, and minimizes reflection loss. At 2.4 GHz, the metasurface achieves 1-bit phase responses of 0° and 180°, with a reflection amplitude exceeding 0.72, demonstrating excellent reflective performance. Moreover, as the 2.4 GHz frequency is closely related to wireless communication bands, this programmable metasurface shows significant potential in the field of wireless communication encryption. By integrating dual varactor diodes, the design enables 2-bit phase control with reflection phase angles of 0°, 90°, 180°, and 270°. To validate the design, a 1-bit metasurface structure was fabricated and tested, with experimental results showing a high degree of consistency with simulations, highlighting the potential of this structure in enhancing wireless communication security.
Possible structures of skyrmion states in chiral ferromagnetic films with spatially modulated uniaxial anisotropy
Authors: Vakhitov R M , Akhmetova A A , Filippov M A 
Published: November 2024

Abstract
In this paper, the stabilization conditions, structure, and properties of possible vortex-like inhomogeneities, including kπ-skyrmions k = 0, 1, 2, 3, 4, in a uniaxial multilayer disk with a columnar defect in the center are investigated based on micromagnetic modeling. Their stability diagrams depending on the Dzyaloshinskii–Moriya interaction, the magnitude of magnetic anisotropy and the defect parameters are determined. New types of vortex-like inhomogeneities that can arise in such samples are found. The obtained data can be used to create artificial regions of nucleation, capture and pinning of magnetic skyrmions, which can provide greater reliability of data storage in spintronic logical devices.
A remaining useful life prediction method for rotating machinery based on interactive BiLSTM
Authors: Li Guofa , Yu Liyao , He Jialong , Zhang Wei , Liu Shaoyang , Wei Jingfeng 
Published: November 2024

Abstract
Rotating machinery, as a key component of mechanical equipment, plays a crucial role in ensuring the reliability and safety of the equipment. This article proposes a RUL prediction framework based on interactive bidirectional long short-term memory (IT-BiLSTM) and function fitting, aiming to improve the accuracy of RUL prediction in rotating machinery. Firstly, to unify the failure threshold under different working conditions, a data interception method based on root mean square is proposed, and empirical mode decomposition is used to reconstruct the intercepted signals; then, 16 features are extracted, and health indicator (HI) is constructed through IT-BiLSTM, which is mapped to the [0,1] interval; finally, the time when HI is 0 is found through function fitting, which is the current RUL. The accuracy of the proposed method is verified using two datasets. The results show that the proposed IT-BiLSTM can more accurately predict the RUL of rotating machinery.
Traffic signal current prediction algorithm based on CNN and LSTM
Authors: Feng Weijia , Qi Siyao , Guo Jia , Zuo Xinyu , Chen Yunhe , Zhu Yichen 
Published: November 2024

Abstract
Traffic signal failures can lead to severe accidents and citywide traffic disruptions, making their reliable operation essential. This study collected real-world data from intersection traffic signals and constructed a dataset. Based on the current data from traffic signals, the formatted pass-dot product attention-LSTM (FD-LSTM) model was proposed. The model utilizes one-dimensional convolution and max pooling for feature extraction, employs dual LSTM units to process forward and backward information, incorporates Dropout to prevent overfitting, and uses the dot-product attention mechanism to enhance the importance of key features. The model is trained using the Adam optimization algorithm. Comparative experiments demonstrate that the FD-LSTM model outperforms other models.
Room-temperature ferromagnetic MnGa nanoparticles in dilute magnetic semiconductor (Ga, Mn)As thin film: preparation and characterization
Authors: Duan Juanmei , Li Zichao , Begeza Viktor , Ruan Shuangchen , Zeng Yu-Jia , Tang Wei , Tsai Hsu-Sheng 
Published: November 2024

Abstract
The GaAs based diluted magnetic semiconductor, (Ga, Mn)As, with the unique advantage of manipulating the spin and charge was widely investigated in the scientific community and considered as a potential material for the spintronic devices. However, its Curie temperature (T
c), which is limited to around 200 K, hinders the research progress of diluted magnetic semiconductors for potential device applications. Herein, we propose an approach to prepare the MnGa nanoparticles embedded in (Ga, Mn)As matrix using the magnetron sputtering deposition of Mn on GaAs surface, followed by the nano-second pulsed laser annealing (PLA), which gives a T
c above 400 K. We demonstrate that the MnGa nanoparticles are only formed in (Ga, Mn) As thin film during the nano-second PLA under a critical range of energy density (0.4–0.5 J cm−2). The highest achieved coercivity, saturation magnetization and remanent magnetization are 760 Oe, 11.3 emu cm−3 and 9.6 emu cm−3, respectively. This method for preparing the hybrid system of ferromagnetic metal/dilute magnetic semiconductor builds a platform for exploring the interesting spin transport phenomenon and is promising for the application of spintronic devices.
Floquet theory and stability analysis for Hamiltonian PDEs
Authors: Bronski Jared C , Mikyoung Hur Vera , Marangell Robert 
Published: November 2024

Abstract
We analyze Floquet theory as it applies to the stability and instability of periodic traveling waves in Hamiltonian PDEs. Our investigation focuses on several examples of such PDEs, including the generalized KdV and BBM equations (third order), the nonlinear Schrödinger and Boussinesq equations (fourth order), and the Kawahara equation (fifth order). Our analysis reveals that the characteristic polynomial of the monodromy matrix inherits symmetry from the underlying PDE, enabling us to determine the essential spectrum along the imaginary axis and bifurcations of the spectrum away from the axis, employing the Floquet discriminant. We present numerical evidence to support our analytical findings.
Multi-winged Lorenz attractors due to bifurcations of a periodic orbit with multipliers

(
−
1
,
i
,
−
i
)
Authors: Karatetskaia Efrosiniia , Kazakov Alexey , Safonov Klim , Turaev Dmitry 
Published: November 2024

Abstract
We show that bifurcations of periodic orbits with multipliers

(
−
1
,
i
,
−
i
)

can lead to the birth of pseudohyperbolic (i.e. robustly chaotic) Lorenz-like attractors of three different types: one is a discrete analogue of the classical Lorenz attractor, and the other two are new. We call them two- and four-winged ‘Simó angels’. These three attractors exist in an orientation-reversing, three-dimensional, quadratic Hénon map. Our analysis is based on a numerical study of a normal form for this bifurcation, a three-dimensional system of differential equations with a Z4-symmetry. We investigate bifurcations in the normal form and describe those responsible for the emergence of the Lorenz attractor and the continuous-time version of the Simó angels. Both for the normal form and the 3D Hénon map, we have found open regions in the parameter space where the attractors are pseudohyperbolic, implying that for every parameter value from these regions every orbit in the attractor has positive top Lyapunov exponent.
Full 3D thermal-hydraulic and electric modelling of quench propagation in HTS conductors
Authors: Zappatore A 
Published: November 2024

Abstract
A fully three-dimensional multi-physics model to simulate quench propagation in high temperature superconducting (HTS) conductors for fusion applications is presented. It accounts for thermal, electric and fluid dynamics throughout the entire transient. The need for high-fidelity models for quench simulations comes from the bulky layouts of many HTS conductors that are being proposed. The model is then validated against experimental data, showing a good agreement on all the relevant quantities (local voltages and temperatures). It is shown that the detailed model improves the quality of the agreement with the measured data with respect to more simplified models. It also allows an insight on the temperature distributions in the conductor cross-section, which can be relevant for the interpretation of experimental data as well as to support the design of quench detection strategies which rely on local temperature variations.
Study on structure and magnetic properties of rare earth terbium-doped ferrite Sr1-xTbxFe12O19
Authors: Tang Yuelong , Wang Changming , Tang Jin , Luo Liang , Wang Chenchen 
Published: November 2024

Abstract
In this paper, Sr1-xTbxFe12O19 (x = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10) ferrite was successfully prepared by ceramic method. The effects of terbium on the structure and magnetic properties of strontium ferrite were investigated. By x-ray diffractometer, it is confirmed that Sr1-xTbxFe12O19 obtained by experiment are all M-type hexagonal ferrite crystals. At the same time, Rietveld finishing was carried out on the prepared samples with fullprof software. The morphologic analysis using emission scanning electron microscope showed that the proportion of hexagonal flake crystals increased with the increase of dopant Tb. Elemental analysis of the samples was performed by EDAX/EDS spectra. The magnetic properties of powder ferrite were measured by hysteresis loop tester, and the magnetic properties of its block were measured by B-H tester. When Tb = 0.04 mol, the magnetic properties of ferrite are the best. The difference in ionic radii between Tb3+ (0.923 Å) and Sr2+ (1.12 Å) allows Tb3+ to form a unique occupancy behavior that affects the formation of the phases, which changes the structure and magnetic properties of Sr1-xTbxFe12O19.
Effect of electromagnetic radiations on the dynamics of a five-chain coupled inertial Hopfield neural network and control of multi-stability with the selection of a desired attractor
Authors: Dongmo T N Sogui , Kengne Jacques , Chedjou Jean Chamberlain 
Published: November 2024

Abstract
In this paper, we investigate the effect of electromagnetic radiation on the dynamics of a network consisting of five chain-coupled inertial Hopfield neurons. The study revealed that the neural system designed such a way involves several complex phenomena, namely Hopf bifurcation, chaos, hyperchaos and the coexistence of up to thirty-two attractors in phase space. The complexity specific to our system is due to the higher number of equilibrium points, namely two hundred and forty-three. Under the conditions of safe functioning of our neural system (chaos or hyperchaos), we have been able to observe that electromagnetic radiation has a harmful character for the system, because we found for a range of variation in the intensity of the electromagnetic feedback induction current a coexistence of chaotic and periodic states (epileptic state). We then controlled the multi-stability using a desired attractor selection scheme, with the aim of suppressing the pathological state. All the work carried out in this contribution is done with the help of dynamical system analysis tools such as the bifurcation diagram, the spectrum and the maximum exponent of Lyapunov, phase portraits and basins of attraction. The numerical scheme used is the Runge–Kutta-4. In order to validate the numerical results, we use analog calculation and some results were derived from the PSpice software. These results are in good accordance in amplitude and location on the plane to those of numerical simulations.
Design and synchronization control application of a new five-dimensional memristor CNN conservative hyperchaotic system
Authors: Zhang Jie , Liu Enze 
Published: November 2024

Abstract
Incorporating memristors into a cellular neural network (CNN) and introducing chaotic characteristics can generate highly complex and unpredictable dynamic behaviors. To advance this research area, this paper proposes a new five-dimensional memristor CNN conservative hyperchaotic system and systematically analyzes its dynamic properties. The analysis content includes equilibrium point analysis, Poincaré sections, Lyapunov exponent spectra, bifurcation diagrams, two-parameter Lyapunov exponent spectra, complexity assessment, homogeneous and heterogeneous extreme multistability, etc In addition, the simulation circuit for the new system is designed and constructed. The digital circuit of the new system is implemented using a microcontroller (MCU). After running simulations, the experimental results from the analog circuit, digital circuit, and numerical simulation are consistent with each other, demonstrating the feasibility of the circuit implementation. Finally, two different synchronization control strategies are employed to achieve synchronization control within a finite time.
Flow characteristics analysis and application research of multi-branch piping
Authors: Zhang Pengfei , Lin Yuhong , Yang Rongchao , Zeng Bo , Shen Longwu , Tian Jiali , Miao Qian 
Published: November 2024

Abstract
This study examines the flow characteristics of multi-branch piping and provides production guidance for tobacco-specific ventilation rate standard rods (VRSRs), focusing on VRSRs within a multi-branch pipeline structure as the research subject. The present work analyses the flow resistance, and flow distribution on the influence of each piping section volume flow. By adopting the iterative method to appropriately construct the mathematical model of the VRSR, an effective technique is developed for thoroughly examining specific VRSRs. The performance of these customized VRSRs is then methodically assessed through repeatability and stability tests, and their suitability is further analyzed by employing five types of ventilation rate test equipment. The main findings reveal: (1) Customized VRSRs exhibit high repeatability and stability; (2) Customized VRSRs are compatible with five common types of ventilation rate testing equipment. Consequently, the model offers scientific theoretical guidance for the production of tobacco-specific VRSRs. Additionally, the study serves as a practical case reference for the production of multi-branch piping systems.
Theoretical Performance Evaluation of Wide-band Diffraction-limited Coronagraph for the Next-generation Segmented Large Telescopes
Authors: Kojima Reiki , Satoshi Itoh , Ota Shunsuke , Yuji Ikeda , Bessho Taiki , Matsuo Taro 
Published: November 2024

Abstract
We investigate the raw-contrast mitigation ability of the spectroscopic coronagraph. We consider a mis-modulation of the complex amplitude by the transmissive focal-plane mask that is an intrinsic problem dependent on the spectral resolving power of a grating in a spectroscopic coronagraph, stellar angular radius, and non-common path error (NCP) that is due to chromaticity in the active wavefront control (WFC) as limitation factors to the performance of the spectroscopic coronagraph. Concerning the impact of the mis-modulation and stellar angular radius under the assumption with the an achromatic WFC, we found that the spectroscopic coronagraph potentially archives the raw-contrast of 1.25 × 10−10 at the spectral resolving power R greater than or equal to 2000 at

2

λ

/

D

with the 10 pc distant solar radius 0.93 mas. It corresponds to approximately 0.03λ/D where the wavelength λ is 800 nm and telescope diameter D is 6 m. The inner working angle (defined as the minimal angular distance where planetary throughput is the maximal throughput) of the spectroscopic coronagraph is

2

λ

/

D

. In addition, we found that the NCP limits the raw-contrast mitigation ability to 7.3 × 10−11 and 5.5 × 10−10 at

2

λ

/

D

for 3% and 8% spectral bandwidths, respectively. We conclude that the spectroscopic coronagraph may serve as a promising method of broadband direct imaging of potentially habitable exoplanets located at small inner working angles with the next-generation segmented large telescopes.
High-pass Filter Periodogram: An Improved Power Spectral Density Estimator for Unevenly Sampled Data
Authors: Albentosa-Ruiz Ezequiel , Marchili Nicola 
Published: November 2024

Abstract
Accurate time series analysis is essential for studying variable astronomical sources, where detecting periodicities and characterizing power spectral density (PSD) are crucial. The Lomb–Scargle periodogram, commonly used in astronomy for analyzing unevenly sampled time series data, often suffers from noise introduced by irregular sampling. This paper presents a new high-pass filter (HPF) periodogram, a novel implementation designed to mitigate this sampling-induced noise. By applying a frequency-dependent HPF before computing the periodogram, the HPF method enhances the precision of PSD estimates and periodicity detection across a wide range of signal characteristics. Simulations and comparisons with the Lomb–Scargle periodogram demonstrate that the HPF periodogram improves accuracy and reliability under challenging sampling conditions, making it a valuable complementary tool for more robust time series analysis in astronomy and other fields dealing with unevenly sampled data.
Tetrahedral shape and Lambda impurity effect in 80Zr with a multidimensionally constrained relativistic Hartree-Bogoliubov model*
Authors: Yang 杨 Dan 丹 , Rong 荣 Yu-Ting 宇婷 
Published: November 2024

Abstract
This study investigated the tetrahedral structure in 80Zr and Lambda (Λ) impurity effect in

Zr using the multidimensionally constrained relativistic Hartree-Bogoliubov model. The ground states of both 80Zr and

Zr exhibit a tetrahedral configuration, accompanied by prolate and axial-octupole shaped isomers. Our calculations reveal that there are changes in the deformation parameters

,

, and

upon Λ binding to 80Zr, except for

when Λ occupies p-orbits. Compared to the two shape isomers, the Λ particle exhibits weaker binding energy in the tetrahedral state when occupying the

or

single-particle state. In contrast, the strongest binding occurs for the Λ particle in the

state with tetrahedral shape. Besides, a large Λ separation energy may not necessarily correlate with a significant overlap between the density distributions of the Λ particle and nuclear core, particularly for tetrahedral hypernuclei.
Temporal attention fusion network with custom loss function for EEG–fNIRS classification
Authors: Bunterngchit Chayut , Wang Jiaxing , Su Jianqiang , Wang Yihan , Liu Shiqi , Hou Zeng-Guang 
Published: November 2024

Abstract

Objective. Methods that can detect brain activities accurately are crucial owing to the increasing prevalence of neurological disorders. In this context, a combination of electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) offers a powerful approach to understanding normal and pathological brain functions, thereby overcoming the limitations of each modality, such as susceptibility to artifacts of EEG and limited temporal resolution of fNIRS. However, challenges such as class imbalance and inter-class variability within multisubject data hinder their full potential. Approach. To address this issue, we propose a novel temporal attention fusion network (TAFN) with a custom loss function. The TAFN model incorporates attention mechanisms to its long short-term memory and temporal convolutional layers to accurately capture spatial and temporal dependencies in the EEG–fNIRS data. The custom loss function combines class weights and asymmetric loss terms to ensure the precise classification of cognitive and motor intentions, along with addressing class imbalance issues. Main results. Rigorous testing demonstrated the exceptional cross-subject accuracy of the TAFN, exceeding 99% for cognitive tasks and 97% for motor imagery (MI) tasks. Additionally, the ability of the model to detect subtle differences in epilepsy was analyzed using scalp topography in MI tasks. Significance. This study presents a technique that outperforms traditional methods for detecting high-precision brain activity with subtle differences in the associated patterns. This makes it a promising tool for applications such as epilepsy and seizure detection, in which discerning subtle pattern differences is of paramount importance.
ITER-relevant 600 s steady-state extraction of negative hydrogen ions at the test facility ELISE
Authors: Wünderlich D. , Riedl R. , Fröschle M. , Heiler A. , Navarro A. , Yordanov D. , Döring A. , Fantz U. 
Published: November 2024

Abstract
The neutral beam heating system for the future international fusion experiment ITER will be based on radio-frequency driven ion sources delivering a large (≈1 × 2 m2) and homogeneous negative hydrogen or deuterium ion beam of several ten Amperes for several hundred seconds. The size scaling experiment ELISE (Extraction from a Large Ion Source Experiment) is an integral part of the R&D road-map towards the ITER neutral beam heating system. Recently, 90% of the ITER target for the extracted current density was achieved in hydrogen for 600 s, increasing the pulse length over which such current densities can be achieved by a factor of more than ten. For ten second beam pulses the ITER target current density was achieved. These breakthrough results are made possible by using a steady-state capable high-voltage power supply together with an improved version of internal potential rods and a modified topology of the magnetic filter field.
Remarks on q-difference opers arising from quantum toroidal algebras
Authors: Feigin B , Jimbo M , Mukhin E 
Published: November 2024

Abstract
We propose a conjectural correspondence between the spectra of the Bethe algebra for the quantum toroidal

gl

2

algebra on relaxed Verma modules, and q-hypergeometric opers with apparent singularities. We introduce alongside the notion of apparent singularities for linear q-difference operators and discuss some of their properties. We also touch on a generalization to

gl

n

.