bluuebunny/crossref_metadata_2025 huggingface dataset:
DC and AC characteristics of Si/SiGe based vertically stacked complementary-tunneling FETs
Authors: Thoti Narasimhulu , Li Yiming
Published: September 2023

In this paper, electrical characteristics of a complementary tunneling field effect transistor (CTFET) is studied computationally for the first time. The design of CTFET is carried with 3D vertically stacked channels (multiple) of n-TFET on top of the p-TFET with gate-all-around (GAA) nanosheet SiGe options. The CTFET technology (using CFETs) is examined for emerging technology nodes as a potential alternative to conventional TFETs. Here, the device level design of CTFET is strictly monitored with DC characteristic behavior under the influence of process variability conditions (traps and temperature). The performance analysis is extended to analyze the scalability of CTFET under critical dimensions (n- to p-TFET separation, nanosheet pitch, and so on), and find that it is highly scalable. The circuit analysis of CTFET-inverter show high-noise margin (NM) and voltage gains compared to the conventional strained-Si GAA-TFETs at the supply range (V
D
D) from 0.7 ≥ V
D
D ≥ 0.2 V. In addition, the CTFET-inverter circuit performance is analyzed with miller capacitance, power delay product, and intrinsic delay, respectively. Improved circuit performance, followed by 12.5% and 21.5% improvements in low and high NMs (NML and NMH) are seen in CTFETs compared to conventional TFETs.
Directional dependence of band gap modulation via uniaxial strain in MoS2 and TiS3
Authors: Armstrong Alex , McKenna Keith P , Wang Yue
Published: September 2023

Strain is widely employed to modulate the band structures of two-dimensional (2D) van der Waals (vdW) materials. Such band engineering with strain applied along different crystallographic directions, however, is less explored. Here, we investigate the band gap modulation of layered chalcogenides, MoS2 and TiS3, and the dependence of their band gaps on the directions of applied strain, using first-principles calculations. The band gap transition in MoS2 is found to reduce in energy linearly as a function of increasing tensile strain, with a weakly directional-dependent gradient, varying by 4.6 meV/% (from −52.7 ± 0.6 to −57.3 ± 0.1 meV/%) from the zigzag to armchair directions. Conversely, the band gap in TiS3 decreases with strain applied along the a lattice vector, but increases with strain applied in the perpendicular direction, with a non-linear strain-band gap relationship found between these limits. Analysis of the structure of the materials and character of the band edge states under strain helps explain the origins of the stark differences between MoS2 and TiS3. Our results provide new insights for strain engineering in 2D materials and the use of the direction of applied strain as another degree of freedom.
Adsorption of sulfur-containing contaminant gases by pristine, Cr and Mo doped NbS2 monolayers based on density functional theory
Authors: Wu Dandan , Ma Aling , Liu Zhiyi , Wang Zhenzhen , Xu Fang , Fan Guohong , Xu Hong
Published: September 2023

The adsorption and sensor performance of hazardous gases containing sulfur (SO2, H2S and SO3) on pristine, Cr and Mo doped NbS2 monolayers (Cr-NbS2 and Mo-NbS2) were investigated in detail based on density functional theory. The comparative analysis of the parameters such as density of states, adsorption energy, charge transfer, recovery time and work function of the systems showed that the pristine NbS2 monolayer have poor sensor performance for sulfur-containing hazardous gases due to weak adsorption capacity, insignificant charge transfer and insignificant changes in electronic properties after gas adsorption on the surface. After doping with Cr atoms, the adsorption performance of Cr-NbS2 was significantly improved, and it can be used as a sensor for SO2 and H2S gases and as an adsorbent for SO3 gas. The adsorption performance of Mo-NbS2 is also significantly improved by doping with Mo atoms, and it can be used as a sensor for H2S gas and as an adsorbent for SO2 and SO3 gas. Therefore, Cr-NbS2 and Mo-NbS2 are revealed to be sensing or elimination materials for the harmful gases containing sulfur (SO2, H2S and SO3) in the atmosphere.
Point-of-care AI-assisted stepwise ultrasound pneumothorax diagnosis
Authors: Kim Kyungsang , Macruz Fabiola , Wu Dufan , Bridge Christopher , McKinney Suzannah , Al Saud Ahad Alhassan , Sharaf Elshaimaa , Sesic Ivana , Pely Adam , Danset Paul , Duffy Tom , Dhatt Davin , Buch Varun , Liteplo Andrew , Li Quanzheng
Published: September 2023

Objective. Ultrasound is extensively utilized as a convenient and cost-effective method in emergency situations. Unfortunately, the limited availability of skilled clinicians in emergency hinders the wider adoption of point-of-care ultrasound. To overcome this challenge, this paper aims to aid less experienced healthcare providers in emergency lung ultrasound scans. Approach. To assist healthcare providers, it is important to have a comprehensive model that can automatically guide the entire process of lung ultrasound based on the clinician’s workflow. In this paper, we propose a framework for diagnosing pneumothorax using artificial intelligence (AI) assistance. Specifically, the proposed framework for lung ultrasound scan follows the steps taken by skilled physicians. It begins with finding the appropriate transducer position on the chest to locate the pleural line accurately in B-mode. The next step involves acquiring temporal M-mode data to determine the presence of lung sliding, a crucial indicator for pneumothorax. To mimic the sequential process of clinicians, two DL models were developed. The first model focuses on quality assurance (QA) and regression of the pleural line region-of-interest, while the second model classifies lung sliding. To achieve the inference on a mobile device, a size of EfficientNet-Lite0 model was further reduced to have fewer than 3 million parameters. Main results. The results showed that both the QA and lung sliding classification models achieved over 95% in area under the receiver operating characteristic (AUC), while the ROI performance reached 89% in the dice similarity coefficient. The entire stepwise pipeline was simulated using retrospective data, yielding an AUC of 89%. Significance. The step-wise AI framework for the pneumothorax diagnosis with QA offers an intelligible guide for each clinical workflow, which achieved significantly high precision and real-time inferences.
Tomographic optical emission spectroscopy of an atmospheric pressure plasma jet and surface ionization waves on planar and structured surfaces
Authors: Bentz Brian Z
Published: September 2023

In this paper, an approach for 3D plasma structure diagnostics using tomographic optical emission spectroscopy (Tomo-OES) of a nanosecond pulsed atmospheric pressure plasma jet (APPJ) is presented. In contrast to the well-known Abel inversion, Tomo-OES does not require cylindrical symmetry to recover 3D distributions of plasma light emission. Instead, many 2D angular projections are measured with intensified cameras and the multiplicative algebraic reconstruction technique is used to recover the 3D distribution of light emission. This approach solves the line-of-sight integration problem inherent to optical diagnostics, allowing recovery of localized OES information within the plasma that can be used to better infer plasma parameters within complex plasma structures. Here, Tomo-OES was applied to investigate an APPJ operated with helium in ambient air and impinging on planar and structured dielectric surfaces. Surface charging caused the guided streamer from the APPJ to transition to a surface ionization wave (SIW) that propagated along the surface. The SIW experienced variable geometrical and electrical material properties as it propagated, leading to 3D configurations that were non-symmetric and spatially complex. Light emission from He, N

2
+

, and N2 were imaged at ten angular projections and the respective time-resolved 3D emission distributions in the plasma were then reconstructed. The spatial resolution of each tomographic reconstruction was 7.4 µm and the temporal resolution was 5 ns, sufficient to observe the guided streamer and the effects of the structured surface on the SIW. Emission from He showed the core of the jet and emission from N

2
+

and N2 indicated effects of entrainment of ambient air. Penning ionization of N2 created a ring or outer layer of N

2
+

that spatially converged to form the ‘plasma bullet’ or spatially diverged across a surface as part of a SIW. The SIW entered trenches of size 150 µm, leading to decreases in plasma light emission in regions above the trenches. The plasma light emission was higher in some regions with trenches, possibly due to effects of field enhancement.
Correlations between reverse bias leakage current, cathodoluminescence intensity and carbon vacancy observed in 4H-SiC junction barrier Schottky diode
Authors: Ho Lok-Ping , Li Si-hua , Lin Tianxiang , Cheung Jack , Chau Tony , Ling Francis Chi-Chung
Published: September 2023

Reverse bias currents of ten commercial junction barrier Schottky diodes were measured, and the dies were studied by scanning electron microscope (SEM) and cathodoluminescence (CL) after the de-capsulation of the diodes. Defect emissions (DEs) of 2.62 eV were observed in all the CL spectra. By comparing the SEM images, the integral CL intensity spatial mappings and the reverse bias leakage currents, correlations between the leakage current, the integral CL intensity and the Al-implantation process were established. The data of reverse bias leakage current against the reverse bias voltage taken at room temperature followed the Poole Frenkel emission from the Z
1/Z
2 carbon vacancy states to the conduction band. The DE at 2.62 eV is associated with the electronic transition from Z
1/Z
2 to the valence band. The current observation also opens up the feasibility of screening off SiC diodes with large leakage current during production by inspecting the CL intensity before the device fabrication is complete.
A novel interior seed addition to improve the levitation force and the trapped field of multi-seeded YBCO bulk superconductors
Authors: Abulaiti Abulizi , Wan-Min Yang
Published: September 2023

Top multi-seeded technique (TMS) is a cost-effective and time-saving method in fabricating larger size high-quality REBCO bulk superconductors. However, the physical properties of the samples prepared by the TMS technique are clearly reduced compared to the single domain samples, especially around the grain boundaries between the neighboring grains. Here we have proposed a novel Inner-Top Multiple-Seeding (IT-MS) technique, which can be used to design and optimize the shapes and space configuration of the single-domain YBCO grains, so as to improve the physical properties of multi-seeded REBCO bulk sample. These have been verified with 60 × 20 × 13 mm3 parallelepiped YBCO bulk superconductors. The levitation force of 112.8 N (77 K, 0.5 T) is achieved in the sample prepared by the IT-MS method with two top seeds and one interior seed, which is 25.2% and 16.9% higher than that of the samples prepared using the TMS method with only two and three top seeds. The trapped field of the IT-MS sample is not only higher than that of the TMS sample, but also the magnetic field coupling ratio is significantly enhanced from 44.2% to 65.1%. The results indicate that the IT-MS technique is helpful to improve the physical properties and homogeneities of the multi-seeded YBCO bulk samples, especially effective for the fabrication of high-quality larger size REBCO bulk superconductors.
Resonance fluorescence of noisy systems
Authors: Bogaczewicz Rafał A , Machnikowski Paweł
Published: September 2023

Light scattering from resonantly or nearly resonantly excited systems, known as resonance fluorescence (RF), has been gaining importance as a versatile tool for investigating quantum states of matter and readout of quantum information, recently including also the inherently noisy solid state systems. In this work we develop a general theory of RF in the low excitation limit on systems in which the transition energy is subject to noise for two important classes of noise processes: white noise fluctuations that lead to phase diffusion and an arbitrary stationary Markovian noise process on a finite set of states. We apply the latter to the case of random telegraph noise (TN) and a sum of an arbitrary number of identical random TN contributions. We show that different classes of noise influence the RF spectrum in a characteristic way. Hence, the spectrum carries information on the characteristics of noise present in the physical system.
Creation and dynamics of spin fluctuations in a noisy magnetic field
Authors: Delpy J , Liu S , Neveu P , Roussy C , Jolicoeur Th , Bretenaker F , Goldfarb F
Published: September 2023

We theoretically and numerically investigate the spin fluctuations induced in a thermal atomic ensemble by an external fluctuating uniaxial magnetic field, in the context of a standard spin noise spectroscopy (SNS) experiment. We show that additional spin noise is excited, which dramatically depends on the magnetic noise variance and bandwidth, as well as on the power of the probe light and its polarization direction. We develop an analytical perturbative model proving that this spin noise first emerges from the residual optical pumping in the medium, which is then converted into spin fluctuations by the magnetic noise and eventually detected using SNS. The system studied is a spin-1 system, which thus shows both Faraday rotation and ellipticity noises induced by the random magnetic fluctuations. The analytical model gives results in perfect agreement with the numerical simulations, with potential applications in future experimental characterization of stray field properties and their influence on spin dynamics.
Low lead inorganic Zn-based mixed-halide perovskites CsPb0.625Zn0.375I3−β
X
β
(X = Cl or Br) for energy generation with 23.5% efficiency
Authors: Kaur Navdeep , Madan Jaya , Mohammed Mustafa K A , Samajdar D P , Khalid Hossain M , Pandey Rahul
Published: September 2023

Hybrid perovskite (HP) solar cells have garnered significant attention in recent years for their excellent light absorption, long carrier lifetime, and high diffusion length, resulting in high power conversion efficiency and superior optical performance compared to silicon solar cells. However, the organic component in HP solar cells is vulnerable to thermal variations and the presence of lead (Pb) poses a threat to the environment. To address these issues, this work proposes the use of all-inorganic halide perovskite (IHP) materials with low lead content as the absorber layer in four different perovskite solar cell configurations: CsPb0.625Zn0.375I2Br, CsPb0.625Zn0.375IBr2, CsPb0.625Zn0.375I2Cl, CsPb0.625Zn0.375ICl2. In addition, owing to the consideration novel IHP materials, it is important to identify the appropriate properties of transport layers since conventional transport layers are best suited to conventional organic–inorganic halide perovskites and may not work well with proposed IHP. Therefore, the appropriate electron transport layer (ETL) has also been investigated through optimization of electron affinity (4.0 eV − 4.23 eV), mobility (0.004 cm2/Vs to 4 cm2/Vs), and donor doping density (1015 cm−3 to 1018 cm−3). The device performance has been further analysed and optimized by varying the active layer thickness. The selected ETL is then combined with the absorber layers to evaluate performance. The effect of varying the thickness of the absorption layer is observed in all four device arrangements. Simulation results show that CsPb0.625Zn0.375ICl2 performed best among the mentioned absorber materials, with a power conversion efficiency of 23.5% with ETL parameters of 4.00 eV (electron affinity, χ), 4 cm2/Vs (electron mobility, μ
n), 1×1018 cm−3 (donor doping density, Nd) and absorber layer thickness of 500 nm. Proposed work may open a window for the development of a new class of environment friendly and stable perovskite solar cells in future.
Effect of Al addition on microstructure and wetting properties of quinary lead-free solder alloy systems
Authors: Oguz Serkan , Erer Ahmet Mustafa
Published: September 2023

In this study, the wetting and microstructural properties of SACBi-xAl (x = 0.05, 0.1, 0.3, 0.5, and 0.6%) quinary lead-free solder alloys produced by adding various amounts of Al to the quaternary SAC-1Bi lead-free solder alloy (wt%) were investigated. The wetting and microstructural properties of Al-added quinary lead-free solder alloys on Cu substrate in an Ar gas atmosphere were investigated. It was reported that the best wetting angle (38.44° for the 325 °C temperature value) and melting temperature (212.5 °C) belonged to the SACBi-0.1Al solder alloy. When the microstructural properties are examined, it is seen with the help of SEM images that the CuAl IMC phase, which is rich in Al, has replaced Cu6Sn5 and Ag3Sn IMCs.
Asymmetric space-dependent systems: partial stabilization through the addition of noise and exact solutions for the corresponding nonlinear Langevin equations
Authors: Fa Kwok Sau , Ho Choon-Lin , Matos Y B , da Luz M G E
Published: September 2023

In many instances, the dynamical richness and complexity observed in natural phenomena can be related to stochastic drives influencing their temporal evolution. For example, random noise allied to spatial asymmetries may induce stabilization of otherwise diverging trajectories in dynamical systems. However, to identify how exactly this takes place in actual processes usually is not a simple task. Here we unveil a few trends leading to dynamical stabilization and diversity of behavior by introducing Gaussian white noise to a class of exactly solvable non-linear deterministic models displaying space-dependent drifts. For the resulting nonlinear Langevin equations, the associated Fokker-Planck equations can be solved through the similarity method or the Fourier transform technique. By comparing the cases with and without noise, we discuss the changes in the systems dynamical characteristics. Simple examples of drift and diffusion coefficients are explicitly analyzed and comparisons with some other models in the literature are made. Our study illustrates the rich phenomenology originated from spatially heterogeneous dynamical systems under the influence of white noise.
Low and intermediate energy cross section analysis of p-p and p-d elastic scattering using modified phase amplitude method for electromagnetic distorted nuclear interaction
Authors: Swain B , Laha U , Behera A K
Published: September 2023

The traditional phase function method is regarded as a resourceful tool for computing scattering phase shifts for quantum mechanical potential scattering involving local interactions. For the local plus a nonlocal potential the conventional phase function method does not hold good. In such a situation one has to modify it. The modified variable phase method is adapted here to treat the Manning-Rosen (MR) plus Graz nonlocal separable potential for constructing an exact expression for the phase function with rigorous inclusion of the electromagnetic effect. The merit of our analytical result is demonstrated by computing elastic scattering phase parameters and differential scattering cross sections for proton-proton (p − p) and proton-deuteron (p − d) systems which are in sensible agreement with previous works.
Predefined-time smooth stability analysis of nonlinear chaotic systems with applications in the PMSM system and Hindmarsh-Rose neuron model
Authors: Ma Ru-Ru , Huang Zhixiang , Ma Zhicai
Published: September 2023

This article investigates the predefined-time stabilization of nonlinear chaotic systems with applications in the permanent magnet synchronous motor (PMSM) system and Hindmarsh-Rose neuron model. Distinguished from the traditional predefined-time control methods, this investigation develops the smooth control protocols, in which the discontinuous absolute value and signum functions are not used anymore, so that the unfavorable chattering phenomenon can be avoided effectively. By the Lyapunov stability analysis, the sufficient condition is derived to achieve the predefined-time stable for nonlinear chaotic systems, in which the upper-bound time estimation (TE) of arriving at the stable state is explicit in contrast to the traditional finite-/fixed-time convergence. Specifically, the analytical results are successfully applied into stabilizing the PMSM system and Hindmarsh-Rose neuron model within the predefined-time. Finally, the numerical simulations for stabilizing the chaotic PMSM system and Hindmarsh-Rose neuron model verify the effectiveness and advantages of theoretical analysis.
Path integral treatment of a Klein Gordon particle with generalized inverse Quadratic Yukawa potential
Authors: Aid Salah Eddine , Boukabcha Hocine , Hemis Mohamed
Published: September 2023

We solved the Klein–Gordon equation for a generalized inverse quadratic Yukawa (GIQY) potential via path integrals approach. We applied approximations to deal with the terms 1/r
2 and 1/r. A path integral representation of Green’s function relating to a particle moving in a mixture of equal vector and scalar potentials was established. To integrate Green’s function, a space-time transformation was successfully used, and the present problem was reduced to a previously known modified Pöschl-Teller potential problem. The integrated Green’s function contains important information about the considered system, from which we obtained energy eigenvalues and the corresponding normalized eigenfunctions for various values of n and ℓquantum numbers. Numerical results, Schrödinger solutions, and special cases such as the modified screened Coulomb plus inversely quadratic Yukawa potential, Kratzer potential, Yukawa potential, and Coulomb potential were also considered. These results are largely consistent with previous studies.
Development of substrate free polymer composite for Pb2+ ion sensor
Authors: Mane Savita S , Joshi Girish M
Published: September 2023

In the present study we focused on utilizing differential pulse voltammetry (DPV) for detecting Pb2+ ions by electrochemical technique. Polyvinyl butyral (PVB) and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) based composite system (PVB/PEDOT:PSS/MoS2) (PPM) modified by Molebdenum disulphide (MoS2). Structural characterization of PPM composite was done by x-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy, revealing phase transitions and chemical functionalities within the ternary system. E2g and A1g Raman active modes related C
α
-C
β
interactions were observed by Raman spectroscopy. Scanning electron microscopy (SEM) forseen uniform filler distribution in homogeneous polymer matrix. Atomic force microscopy (AFM) reveals decreased surface roughness. Sessile drop contact angle measurements were confirmed hydrophilic properties, feasible for sensing applications. Cyclic voltammetry was performed in a 1 M acetate buffer solution, aligned with electrochemical impedance spectroscopy (EIS) results. The sensing capacity of PPM films was examined using differential pulse voltammetry (DPV). Sensor demonstrated effective detection of Pb2+ ions, with a low detection limit (LOD) of 27.77 μM and a linear detection range of 25–60 μM. Developed sensor exhibited excellent repeatability (with relative standard deviation (RSD) 0.6%) and strong selectivity. Sensor electrode performed appriciable trace of Pb2+ ions in drinking water at high concentration.
Thin film flow, heat transfer and viscous dissipation effects on vertical stretching sheet for different shapes of (Au-Np) dispersed in water
Authors: Hayat Umer , Shahzad Azeem
Published: September 2023

In this article, we present numerical investigation and analysis of thin film flow and heat transfer effects for different shapes of gold nanoparticles on a vertical stretching sheet. There are several uses for thin liquid films, including antireflection coating for lenses. Coating systems must have a smooth, polished surface, low friction, clarity, and strength to satisfy the demands of all of these applications. We consider thin film flow of nanoparticles on a vertical stretching sheet due to their numerous applications. Additionally, we employed water as the base fluid and considered different shapes of gold nanoparticles (blades, cylinders, and platelets). After formulating the problem, we convert nonlinear partial differential equations (PDEs) into ordinary differential equations (ODEs) using a transformation. The resulting nonlinear differential equations have been computed by the BVP4c method. It is examined and graphically assessed how the Nusselt number, temperature, skin friction, and fluid velocity are related. This research suggests that the blade shape has the maximum heat transfer rate and the lowest skin friction coefficient value.
Confluent effects of initial dislocation microstructures on yield behavior in single-crystal tungsten at high temperature
Authors: Xiang Yang , Yu Yuying , Cui Yinan , Hu Jianbo
Published: September 2023

Though it is well known that initial dislocation microstructures play an important role in the deformation behavior of materials, how dislocation microstructures affect the macroscopic properties is still subjected to intensive research due to their complexity. In this work, we use discrete dislocation dynamics (DDD) to understand the effect of initial dislocation microstructures on the dynamic yield behavior of single-crystal tungsten above the critical temperature (800 K). DDD results suggest that the dislocation source length

l

0

and the dislocation density

ρ

0

are responsible for the initial yield stress and the flow stress of tungsten under dynamic loading, respectively. As

ρ

0

and

l

0

increase, the plastic yield mechanism transforms from dislocation-source activation into dislocation-dislocation interactions, resulting in the initial yield stress decreasing and the flow stress increasing. The confluent effects of

ρ

0

and

l

0

on the steady-state flow stress

σ

flow

can be unified by a linear relationship between

σ

flow

and

ρ

0

log

l

0

2
b

.

Our results could be a valuable piece that connects dynamic yield behavior to the initial dislocation microstructures.
Neutrino spin oscillations in a magnetized Polish doughnut
Authors: Dvornikov Maxim
Published: September 2023

We study the gravitational scattering of ultrarelativistic neutrinos off a rotating
supermassive black hole (BH) surrounded by a thick magnetized accretion disk. Neutrinos interact
electroweakly with background matter and with the magnetic field in the disk since neutrinos are
supposed to possess nonzero magnetic moments. The interaction with external fields results in
neutrino spin oscillations. We find that the toroidal magnetic field, inherent in the magnetized
Polish doughnut, does not cause a significant spin-flip for any reasonable strengths of the
toroidal component. The reduction of the observed neutrino flux, owing to neutrino spin
oscillations, is predicted. A poloidal component of the magnetic field gives the main contribution
to the modification of the observed flux. The neutrino interaction with matter, rotating with
relativistic velocities, also changes the flux of neutrinos. We briefly discuss the idea of the
neutrino tomography of magnetic field distributions in accretion disks near BHs.
Periodic Variable Star Classification with Deep Learning: Handling Data Imbalance in an Ensemble Augmentation Way
Authors: Kang Zihan , Zhang Yanxia , Zhang Jingyi , Li Changhua , Kong Minzhi , Zhao Yongheng , Wu Xue-Bing
Published: September 2023

Time-domain astronomy is progressing rapidly with the ongoing and upcoming large-scale photometric sky surveys led by the Vera C. Rubin Observatory project (LSST). Billions of variable sources call for better automatic classification algorithms for light curves. Among them, periodic variable stars are frequently studied. Different categories of periodic variable stars have a high degree of class imbalance and pose a challenge to algorithms including deep learning methods. We design two kinds of architectures of neural networks for the classification of periodic variable stars in the Catalina Survey’s Data Release 2: a multi-input recurrent neural network (RNN) and a compound network combing the RNN and the convolutional neural network (CNN). To deal with class imbalance, we apply Gaussian Process to generate synthetic light curves with artificial uncertainties for data augmentation. For better performance, we organize the augmentation and training process in a “bagging-like” ensemble learning scheme. The experimental results show that the better approach is the compound network combing RNN and CNN, which reaches the best result of 86.2% on the overall balanced accuracy and 0.75 on the macro F1 score. We develop the ensemble augmentation method to solve the data imbalance when classifying variable stars and prove the effectiveness of combining different representations of light curves in a single model. The proposed methods would help build better classification algorithms of periodic time series data for future sky surveys (e.g., LSST).
A wearable EEG system for closed-loop neuromodulation of sleep-related oscillations
Authors: Bressler Scott , Neely Ryan , Yost Ryan M , Wang David , Read Heather L
Published: September 2023

Objective. Healthy sleep plays a critical role in general well-being. Enhancement of slow-wave sleep by targeting acoustic stimuli to particular phases of delta (0.5–2 Hz) waves has shown promise as a non-invasive approach to improve sleep quality. Closed-loop stimulation during other sleep phases targeting oscillations at higher frequencies such as theta (4–7 Hz) or alpha (8–12 Hz) could be another approach to realize additional health benefits. However, systems to track and deliver stimulation relative to the instantaneous phase of electroencephalogram (EEG) signals at these higher frequencies have yet to be demonstrated outside of controlled laboratory settings. Approach. Here we examine the feasibility of using an endpoint-corrected version of the Hilbert transform (ecHT) algorithm implemented on a headband wearable device to measure alpha phase and deliver phase-locked auditory stimulation during the transition from wakefulness to sleep, during which alpha power is greatest. First, the ecHT algorithm is implemented in silico to evaluate the performance characteristics of this algorithm across a range of sleep-related oscillatory frequencies. Secondly, a pilot sleep study tests feasibility to use the wearable device by users in the home setting for measurement of EEG activity during sleep and delivery of real-time phase-locked stimulation. Main results. The ecHT is capable of computing the instantaneous phase of oscillating signals with high precision, allowing auditory stimulation to be delivered at the intended phases of neural oscillations with low phase error. The wearable system was capable of measuring sleep-related neural activity with sufficient fidelity for sleep stage scoring during the at-home study, and phase-tracking performance matched simulated results. Users were able to successfully operate the system independently using the companion smartphone app to collect data and administer stimulation, and presentation of auditory stimuli during sleep initiation did not negatively impact sleep onset. Significance. This study demonstrates the feasibility of closed-loop real-time tracking and neuromodulation of a range of sleep-related oscillations using a wearable EEG device. Preliminary results suggest that this approach could be used to deliver non-invasive neuromodulation across all phases of sleep.
The influence of chemical etching on the surface quality of phase components
Authors: Yuan Zhigang , Zhong Bo , Liu Hongjun , Yan Hao , Li Ang , Tian Liang , Wen Shenglin , Li Jie
Published: September 2023

Large-aperture fused silica phase optical components such as continuous phase plate (CPP) are widely used in large-scale laser devices to achieve beam homogenization and improve beam quality. However, under the action of high-energy lasers, their lower damage threshold seriously restricts their service life and increases cost of using. Compared with other fused silica components, chemical processing technology with hydrofluoric acid solution (HF) is lacking in the processing of phase components because the residual root mean square value (RMS) of phase elements is very high, and it can not guarantee this. Therefore, it is necessary to carry out research on the influence of chemical treatment on phase components. In this paper, we improved the chemical treatment process to achieve the change of residual RMS value not more than 3 nm, and improved the ability of resisting laser damage that the damage threshold of 29J/cm2 was obtained under the test conditions 351nm@3ns. Finally, we successfully mastered the chemical control process of phase components and applied it to the CPPs as other fused quartz materials engineering production process.
Research on hybrid power load matching control method of new energy pumping machine
Authors: Tian Ye , Gao Xiaohui , Tian Danling , Liu Yongguang
Published: September 2023

In order to improve the energy saving effect of new energy pumping machine, the power matching energy saving control of wind energy, electric energy and pumping machine load should be carried out when the actual wind speed is lower than the rated wind speed of the system. In this paper, according to the wind power hybrid transmission system, we study the load matching energy saving control strategy and method that takes into account the simultaneous change of wind speed and load, and propose the hybrid power load matching adaptive energy saving control strategy based on the cascade controller. In the strategy, the motor torque control method is used to eliminate the pressure deviation and realize the system pressure tracking load matching adaptive control, while keeping the motor output torque stable.
Research on vibration frequency of double connected gears in aero-engine field
Authors: Zhang Guangli , Liu Ming , Yang Xiongfei , Liu Xianshuang , Tian Maoquan
Published: September 2023

The finite element simulation method is used to calculate and analyze the vibration frequency of aero-engine double connected gears with different common aero-engine gear materials, different numbers of connecting pins, and different numbers of weight-reducing holes. The analysis results are shown that the first several vibration modes of the double connected gears are first caused by the big gear, the vibration frequency of the double connected gears is almost not affected by the number of connecting pins, the vibration frequency of the double connected gears is little affected by different common aero-engine gear materials, while the vibration frequency of double connected gears is reduced with the increase of the number of weight reduction holes. The design and vibration avoidance reference of double connected gears are provided in the paper.
Simulation and experimental study of active noise barrier based on multiple-channel and decentralized system design
Authors: Hou Zilong , Wu Rui , Hu Wencheng , Yao Kun
Published: September 2023

Active noise barrier (ANB) was helpful to enhance the noise reduction performance of noise barrier especially in low-frequency range. But it was quite difficult to realize an ideal effect in the far-field as most of the exiting work of ANB took the realization of soft boundary at the edge of noise barriers as the target. An active control strategy based on the decentralized system design was proposed in this paper. The virtual sensor technology was used in order to obtain the far-field noise signal with the help of near-field sensor, while multiple-channel design of both centralized system and decentralized system was studied. An experimental ANB system was then built in semi-anechoic chamber. The performance of the above control strategies was calculated with the actual measured parameters, and the advantages and disadvantages of different systems were compared and studied. The effectiveness of the new strategy was verified through the noise reduction tests of active noise control. The ANB established in this paper which was based on decentralized system design, could be extended to large scale usage directly in the future.
Exposure levels of radiofrequency electromagnetic fields from mobile base stations in Mpumalanga province, South Africa
Authors: Rathebe Phoka C.
Published: September 2023

This study assessed the radiofrequency electromagnetic fields (RF-EMF) exposure levels proximal to primary school structures in the Mpumalanga province of South Africa. A calibrated Acoustimeter was used to measure the RF EMF levels at defined distance points of 50 and 100m away from the three mobile base stations, that provide a 4G network coverage. All the measurements were obtained from three mobile stations, each from one district municipality, using 30 minutes intervals for repeated measurements. The measured peak exposure level at 50m was 887 μW/m2 and 905 μW/m2 at 100m. No statistical difference was found when comparing the measurement data obtained at 50 and 100m from the three district municipalities. However, comparison of measurements obtained at 50 and 100m for all base stations were statistically significant, p-value< .002 and p< .003 respectively. The measured RF EMF exposure levels at both distance points were below the reference levels found under International Commission for Non-ionizing Radiation Protection (ICNIRP) RF guidelines. It is therefore essential for mobile base station companies to consider proximity of residential structures when installing new base stations in the future, and regularly maintain the components of mobile base towers, especially in the current state of power load shedding in South Africa.
Development of the remote automatic calibration system of the verification equipment for AC electrical energy meters
Authors: Wang Xinyan , Zhao Dongsheng , Yan Hongrui , Sun Xiaojie , Liu Jianbo , Wang Weizhao
Published: September 2023

The calibration of the verification equipment for AC electrical energy meters (hereinafter referred to as the DUT) was being performed manually till now. A new system for remote automatic calibration of the DUT, which applies cloud server, 4G cellular mobile interconnection technology and virtual serial communication technology, was firstly proposed in this paper. The technical problems of remote automatic calibration of large equipment, and safety problems in equipment transportation, wiring and installation were solved by developing automatic test and management software, remote communication management platform, designing and developing remote control device and special connection terminal base.
A static voltage stability index based on P-V curve for the medium-voltage distribution network with distributed PV
Authors: Li Sheng , Gao Yuan , Jiang Chengcheng
Published: September 2023

With the rapid increase of distributed photovoltaic (DPV) generations, the static voltage stability (SVS) of distribution network (DN) is faced with more and more challenges. Considering the characteristics of DPV and the network structure, an appropriate static voltage stability index (SVSI) in the medium-voltage DN with DPV is studied in this paper. In terms of the limitation of the traditional SVSI that only reflects the load change, based on P-V curve, a novel voltage change rate - network load change rate index (M-index) is proposed. The M-index considers the impacts of double changes in DPV power output and load level. The model of classic 33-node network with a DPV source is established to investigate the proposed M-index. By changing the DPV penetration percentage and the DPV access point, and comparing with the existing Load-index, the validity and superiority of M-index is verified. Comparing with the traditional SVSI, the M-index is more propitious to evaluate the SVS for the medium-voltage DN with DPV.
A current prediction correction control algorithm for permanent magnet synchronous linear motor
Authors: Zheng Zaiping , Wu Hongxing , Fu Jie , Huang Yuping
Published: September 2023

When a permanent magnet synchronous linear motor (PMSLM) is used in a direct drive system, the current loop of drive control system is required to have a high response speed in order to achieve a high dynamic response of the system. With the traditional PI control strategy, the bandwidth of the system’s current loop is limited. In this paper, a predictive correction control algorithm is used in the current loop of permanent magnet synchronous linear motor drive control system. The algorithm is to predict the instruction voltage vector required by the next switching cycle so that the target current of the control system can reach the instruction reference current value within the next switching cycle. It is used to improve the response speed of the system current loop and realize the precise control of the single PWM cycle of the system current loop.
A C-band folded planar low-pass filter utilizing U-shaped probe for high power TR module
Authors: Wang Xi , Yu Huaiqiang , Deng Like , Cheng Bin , Fang Zhiping , Lang Xiaoyuan
Published: September 2023

In this paper, a C-band folded low-pass filter is realized in the planar circuit by utilizing a U-shaped probe. The proposed filter consists of four microstrip patches and a U-shaped probe. The configuration, equivalent circuit and design method of the proposed filter are demonstrated. A prototype of the low-pass filter operating in C-band has been designed, fabricated and measured. The maximum insertion loss of the fabricated filter is about 0.8 dB from 5 GHz to 6 GHz, while the maximum return loss is -11 dB. The out of band rejection is over 30 dB at 12 GHz. The measured results show reasonable correlation with the ideal circuit and the simulated results. The proposed low-pass filter can be used for the high power transmit/receive (TR) module in active electronically scanned array (AESA).
Sensorless vector control approach for the interior PM synchronous machine with DC-offset compensation loop
Authors: Rahman Sadiq Ur , Xia Chaoying , Xiao Pengchao , Yu Jiali , Wang Nannan
Published: September 2023

Two different DC offset compensators for sensorless PMSM, motor drives with wide speed range flux linkage observers, are introduced and compared. The first one is an improved flux observer with PI correction and no need for mover speed and phase adaptation. The second one is a novel flux observer with an active disturbance rejection controller (ADRC) compensator without mover speed adaptation. The ESO built into ADRC is able to detect and compensate for both internal model disturbance and external load disturbance, resulting in a controller with superior dynamic responsiveness and robust regulation. In both scenarios, an injected direct current (DC) offset is calculated and maintained by the PI integral part and ADRC, which effectively compensates for the DC biases and drifts caused by the sampling channels. Compared to the PI controller, ADRC demonstrates greater transient performance and disturbance robustness. The results of theoretical analysis and Matlab simulations have confirmed the feasibility and efficiency of the proposed strategy.
Exploring the application of digital twin technology in the field of artillery equipment protection
Authors: Wu Dalin , Yang Yuliang , Xie Bocheng , Dong Peng
Published: September 2023

This paper addresses the problem that artillery condition assessment work is still stuck in the way of regular maintenance and after-the-fact repair, which makes it difficult to achieve accurate equipment protection, etc. Taking a typical artillery loading system as the research object, this paper uses simulation and experimentation to carry out research on loading system condition assessment by constructing a digital twin system framework for artillery equipment condition assessment, studying the construction of twins, data transmission between physical entities and twins and other key technologies, and providing a reference method for achieving accurate artillery maintenance and protection.
A remaining useful life prediction method based on LSTM-DCGAN for aero-engines
Authors: Shan Yibing , Xiao Lei , Ma Baiteng
Published: September 2023

Turbofan engine is a key component in aerospace. Its health condition determines whether an aircraft can operate reliably. However, it is difficult to predict the remaining useful life (RUL) precisely because of the characteristics of complex operating conditions and various failure modes. To predict the RUL more accurately and make full use of the advantages of neural networks, a RUL prediction model based on a long short-term memory network (LSTM) and deep convolutional generative adversarial network (DCGAN) is proposed and called LSTM-DCGAN in this paper. In the proposed LSTM-DCGAN, DCGAN is used to obtain knowledge of the training dataset, then the generator after pretraining in the DCGAN is attached after an LSTM network for further feature extraction. The effectiveness of the proposed LSTM-DCGAN is validated on the C-MAPSS aero-engine degradation dataset and compared with other methods.
Mimicking sarcolemmal damage in vitro: a contractile 3D model of skeletal muscle for drug testing in Duchenne muscular dystrophy
Authors: Tejedera-Villafranca Ainoa , Montolio Marisol , Ramón-Azcón Javier , Fernández-Costa Juan M
Published: September 2023

Duchenne muscular dystrophy (DMD) is the most prevalent neuromuscular disease diagnosed in childhood. It is a progressive and wasting disease, characterized by a degeneration of skeletal and cardiac muscles caused by the lack of dystrophin protein. The absence of this crucial structural protein leads to sarcolemmal fragility, resulting in muscle fiber damage during contraction. Despite ongoing efforts, there is no cure available for DMD patients. One of the primary challenges is the limited efficacy of current preclinical tools, which fail in modeling the biological complexity of the disease. Human-based three-dimensional (3D) cell culture methods appear as a novel approach to accelerate preclinical research by enhancing the reproduction of pathophysiological processes in skeletal muscle. In this work, we developed a patient-derived functional 3D skeletal muscle model of DMD that reproduces the sarcolemmal damage found in the native DMD muscle. These bioengineered skeletal muscle tissues exhibit contractile functionality, as they responded to electrical pulse stimulation. Sustained contractile regimes induced the loss of myotube integrity, mirroring the pathological myotube breakdown inherent in DMD due to sarcolemmal instability. Moreover, damaged DMD tissues showed disease functional phenotypes, such as tetanic fatigue. We also evaluated the therapeutic effect of utrophin upregulator drug candidates on the functionality of the skeletal muscle tissues, thus providing deeper insight into the real impact of these treatments. Overall, our findings underscore the potential of bioengineered 3D skeletal muscle technology to advance DMD research and facilitate the development of novel therapies for DMD and related neuromuscular disorders.