bluuebunny/crossref_metadata_2025_split huggingface dataset:
30 years in: Quo vadis generalized uncertainty principle?
Authors: Bosso Pasquale , Gaetano Luciano Giuseppe , Petruzziello Luciano , Wagner Fabian 
Published: August 2023

AbstractAccording to a number of arguments in quantum gravity, both model-dependent and model-independent, Heisenberg’s uncertainty principle is modified when approaching the Planck scale. This deformation is attributed to the existence of a minimal length. The ensuing models have found entry into the literature under the term generalized uncertainty principle. In this work, we discuss several conceptual shortcomings of the underlying framework and critically review recent developments in the field. In particular, we touch upon the issues of relativistic and field theoretical generalizations, the classical limit and the application to composite systems. Furthermore, we comment on subtleties involving the use of heuristic arguments instead of explicit calculations. Finally, we present an extensive list of constraints on the model parameterβ, classifying them on the basis of the degree of rigor in their derivation and reconsidering the ones subject to problems associated with composites.
Theoretical predictions and electronic properties of thiolate-protected gold nanocluster: Au44(SR)32
Authors: Sun Yuanze , Yu Xueke , Xu Wenwu , Su Yan , Zhao Jijun 
Published: August 2023

Abstract
Thiolate-protected gold nanoclusters have received extensive attention both experimentally and theoretically due to their excellent physical and chemical properties. However, comprehending the geometric structure of thiolate-protected gold nanoclusters remains a challenging task. Predicting the structural configuration of these ligand-protected gold nanoclusters can enhance our understanding of this class of materials. Due to the current lack of knowledge regarding the structure of Au44(SR)32, we employed the grand unified model (GUM) for gold core stacking and the ring model to describe interfacial interactions between gold cores and the protection motifs. Based on these models, we successfully predicted the geometric structure of Au44(SR)32 clusters and demonstrated partial reproducibility between the calculated absorption spectra and experimental results. Furthermore, by analyzing the energy levels and molecular orbitals, we have identified that the absorption spectra of Au44(SR)32 arise from d→d and d→sp transitions, with the low-energy state primarily resulting from Au44-to-core transitions and the high-energy state from Au44-to-ligand transitions. These findings not only enhance our understanding of Au44(SR)32 clusters but also validate the effectiveness and applicability of GUM and ring model in predicting stable structures of thiolate-protected gold nanoclusters.
Inverse design of transmission-type linear-to-circular polarization control metasurface based on deep learning
Authors: Hu Yanwen , Ma Yaodong , Zhang Tingrong , Li Shoudong , Chen Xiaoqiang 
Published: August 2023

Abstract
To solve the time-consuming and complex design problems, the deep learning method is used to realize the inverse predictive design of a transmission-type linear-to-circular polarization control metasurface (TLCPCM). Firstly, the target-generation neural network model (TGNNM) is constructed based on a fully connected neural network. The model selects the critical features of the required electromagnetic performance as design targets, and maps low-dimensional design targets to high-dimensional electromagnetic performance. Secondly, taking the output data of the TGNNM as input data, an inverse-mapping neural network model (IMNNM) is constructed by a convolutional neural network. The prediction performance of the IMNNM is compared with two other inverse-mapping models. The research results show that the IMNNM outperforms the other two networks. Finally, combining TGNNM and IMNNM, four sets of TLCPCM structural parameters are predicted. The research results show that the electromagnetic performances of the metasurface determined by the predicted structural parameters are generally consistent with the given design targets. On this basis, one experimental sample is manufactured. The measurement results are consistent with the simulation results. The research results demonstrate the validity and feasibility of the inverse predictive design method proposed in this paper.
Analytical input-output modelling of surface dielectric barrier discharge plasma actuator
Authors: Nesaeian M , Homaeinezhad M R 
Published: August 2023

Abstract
Surface dielectric barrier discharge (SDBD) actuators are a type of asymmetric dielectric barrier discharge (DBD) actuator that can be used to generate ions and produce thrust for near-space vehicles. In this paper, a physics-based model for SDBD produced thrust is developed that accounts for geometric and environmental variation between SDBDs. The presented SDBD analytical model (SDBD-AM) is based on models for parallel-plate DBDs but accounts for the ‘virtual electrode’ resulting from changing plasma length that is particular to SDBDs. To validate the model, thrust measurements from 12 different configurations from previous studies were used, and the mean absolute percentage error (MAPE) between each configuration and SDBD-AM was determined. The observed effects on the model were attributed to structural effects including electrode width, electrode spacing, dielectric, and environmental effects including pressure, and the apparent uncertainties are different for each effect. As a result, it was obtained that the MAPE between SDBD-AM and the experimental data for different structures is 11%, and for different pressures, it is 12%. The body force field has been simulated using SDBD-AM and a distribution function in COMSOL software, and the body force profile near the exposed electrode has been validated with a previous numerical model. This model can be used for the design and optimization of SDBD actuators and also in the design of control systems such as spacecraft attitude control in order to increase the accuracy and performance of the controller.
Enhancing photoelectrocatalytic activity and stability of p-Cu2O photocathode through n-TiO2 coating for improved H2 evolution reaction
Authors: Le Hoang V , Ung Thuy T D , Tran Phong D , Mai Huy V , Do Bich D , Nguyen Liem Q 
Published: August 2023

Abstract
This article presents a novel approach to improve both the photoelectrocatalytic activity and stability of the p-Cu2O photocathode. The approach involves the coating of an n-type TiO2 layer using e-beam evaporation with precise controllability of the coating thickness onto the p-type Cu2O electrode, forming a TiO2/Cu2O p/n heterojunction. Such a p/n junction enhances the photoelectrocatalytic activity of the Cu2O electrode by promoting the separation of the photo-generated charge carriers. Additionally, the large bandgap TiO2 coating layer serves as protection, reducing the photocorrosion of Cu2O, thereby improving the stability of the electrode. The n-TiO2/p-Cu2O photocathode shows superior photoelectrochemical H2 evolution activity in comparison to the pristine p-Cu2O photocathode. We have found that the thickness and annealing temperature of TiO2 influence strongly the photocurrent and stability of the resultant TiO2/Cu2O photocathode. The best TiO2/Cu2O photocathode was achieved by coating a 50 nm thick TiO2 layer onto the Cu2O, followed by annealing at 350 °C. This configuration exhibited a large onset photovoltage of 0.58 V vs RHE and a catalytic current density of ∼0.9 mA·cm‒2 at 0 V vs RHE in a pH 7 phosphate buffer, under standard 1 Sunlight illumination.
Exploration on structural stability, electronic and optical properties of Cs-activated and Cs/O-activated Al0.5Ga0.5N thin film and nanowire photocathode surface
Authors: Tian Jian , Liu Lei , Lu Feifei , Zhangyang Xingyue 
Published: August 2023

Abstract
To explore effects of surface activation on AlGaN-based photocathode, this paper analyzes in detail the structural stability, charge transfer, band structure, density of states, absorption coefficient and reflectivity of Cs-activated and Cs/O-activated Al0.5Ga0.5N thin films and nanowires by using first-principles. Our results reveal that adsorption energy of Al0.5Ga0.5N thin films and nanowires adsorbed by Cs will gradually increase as Cs coverage increases, and structural stability will be weakened. Cs-adsorbed thin film surfaces are more stable than nanowire when Cs coverage is same. Cs/O co-adsorbed Al0.5Ga0.5N systems are more stable under high Cs coverage. And Cs/O co-adsorbed Al0.5Ga0.5N possess the most stable structure when the ratio of Cs to O is 2:1. Band structure and density of states imply that Cs and O adsorption introduce new energy levels, which are derived from s, p orbitals of Cs and s orbitals of O, respectively. Furthermore, only when the Cs/O ratio is 2:1, the work function of Al0.5Ga0.5N thin film is lower than that of Cs-only adsorption, which is conducive to electron escape and improving quantum efficiency. Results of optical properties show that Cs activation and Cs/O activation can greatly improve the optical performance of Al0.5Ga0.5N.
High-speed and dynamic measurement of the diffraction efficiency of a grating in a wide wavelength range
Authors: Wang Shenghao , Wang Zhendong , He Zhiping 
Published: August 2023

Abstract
Approximate 5 min are needed to obtain diffraction efficiency of a grating in a wavelength range with 151 sampling points by the currently widely used measurement technique. The time-consuming nature restricts its usage in many dynamic measurements. To this end, we developed a fast measurement technique, and the corresponding measurement is completed in a high speed within 1 s. Meanwhile, dynamic measurement of the efficiency of a grating from 600 nm to 900 nm during a heating procedure is successfully carried out. Our technique could find applications in other circumstances where high-speed measurement is needed.
The research on fault diagnosis of rolling bearing based on current signal CNN-SVM
Authors: Wang Xinghua , Meng Runxin , Wang Guangtao , Liu Xiaolong , Liu Xiaohong , Lu Daixing 
Published: August 2023

Abstract
This article proposes a novel approach to address the issues of low accuracy in fault diagnosis and the difficulty in installing sensors on rolling bearings in mechanical and electrical equipment systems. To accomplish fault diagnosis of rolling bearings, a network structure algorithm based on convolutional neural network (CNN) and support vector machine (SVM) is presented, which incorporates the electric motor current signal. Firstly, the collected electric motor current signal is subjected to a wavelet filter with a soft-hard threshold to eliminate the noise. Secondly, the processed data is fed as input to a one-dimensional CNN to perform feature extraction and dimensionality reduction. Finally, the dimensionality-reduced features are processed by a SVM to diagnose rolling bearing faults. The research results indicate that the proposed method significantly improves the accuracy of rolling bearing fault diagnosis compared to other approaches, with an accuracy of up to 99.01%. This study introduces an innovative approach that can be applied to the field of rolling bearing fault diagnosis, offering valuable insights for research and application in this domain.
Manifold learning-assisted sparse filtering method for machinery fault diagnosis
Authors: Wang Qian , Peng Demin , Jiang Xingxing , Song Qiuyu , Zhu Zhongkui 
Published: August 2023

Abstract
Sparse filtering (SF) has received considerable attentions in the machinery fault diagnosis thanks to its ability to extract the fault-related features using their sparsity. However, the existing SF methods have dilemmas with the empirical selection of model parameters, the loss of fault-related information caused by a screening way for the target mode, and the singularity of results induced by some large-amplitude random impulses (LARIs). Hence, a manifold learning-assisted SF method is proposed for machinery fault-related feature enhancement in this study. First, an improved intrinsic component filtering (ICF) is presented for extracting the multiple modes with feature enhancement, where the parameters of ICF are adaptively determined by using the optimization object to avoid the empirical selection of parameters. Second, the manifold learning is introduced to compress the enhanced multiple modes to overcome the loss of fault-related information; thus the intrinsic manifolds are obtained for disclosing the buried fault-related features and suppressing the band-in noise. Third, an adaptively weighting strategy for these intrinsic manifolds is constructed to obtain a final representative mode for conducting the machinery fault diagnosis. Meanwhile, the LARIs coupled with intrinsic manifolds are calibrated according to their statistical information to resolve the singularity of the representative features. Simulation and experiments show that the proposed method is more effective in extracting fault-related features than some existing methods.
Oxygen-doped NiCoP derived from Ni-MOFs for high performance asymmetric supercapacitor
Authors: Liu Yan , Fan Xiaoyan , Zhang Zikun , Li Chun , Zhang Shuaiyi , Li Zhenjiang , Liu Lin 
Published: August 2023

Abstract
Oxygen doping strategy is one of the most effective methods to improve the electrochemical properties of nickel–cobalt phosphide (NiCoP)-based capacitors by adjusting its inherent electronic structure. In this paper, O-doped NiCoP microspheres derived from porous nanostructured nickel metal–organic frameworks (Ni-MOFs) were constructed through solvothermal method followed by phosphorization treatment. The O-doping concentration has a siginificant influence on the rate performance and cycle stability. The optimized O-doped NiCoP electrode material shows a specific capacitance of 632.4 F-g−1 at 1 A-g−1 and a high retention rate of 56.9% at 20 A g−1. The corresponding NiCoP-based asymmetric supercapacitor exhibits a high energy density of 30.1 Wh kg−1 when the power density is 800.9 W kg−1, and can still maintain 82.1% of the initial capacity after 10 000 cycles at 5 A g−1.
On zonal steady solutions to the 2D Euler equations on the rotating unit sphere
Authors: Nualart Marc 
Published: August 2023

Abstract
The present paper studies the structure of the set of stationary solutions to the incompressible Euler equations on the rotating unit sphere that are near two basic zonal flows: the zonal Rossby–Haurwitz solution of degree 2 and the zonal rigid rotation

Y

1
0

along the polar axis. We construct a new family of non-zonal steady solutions arbitrarily close in analytic regularity to the second degree zonal Rossby–Haurwitz stream function, for any given rotation of the sphere. This shows that any non-linear inviscid damping to a zonal flow cannot be expected for solutions near this Rossby–Haurwitz solution. On the other hand, we prove that, under suitable conditions on the rotation of the sphere, any stationary solution close enough to the rigid rotation zonal flow

Y

1
0

must itself be zonal, witnessing some sort of rigidity inherited from the equation, the geometry of the sphere and the base flow. Nevertheless, when the conditions on the rotation of the sphere fail, the set of solutions is much richer and we are able to prove the existence of both explicit stationary and travelling wave non-zonal solutions bifurcating from

Y

1
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, in the same spirit as those emanating from the zonal Rossby–Haurwitz solution of degree 2.
Students’ perceptual practices with real and virtual images
Authors: Isik Hakan 
Published: August 2023

Abstract
This study examined how university students learn real and virtual images using vision-based perception cues such as binocular parallax, monocular parallax, binocular fuzziness, monocular fuzziness, and convergence. Two activities on the cues were conducted with university students. In the pre-activity, they learned about the perceptual cues and practiced each cue without using a lens or mirror. Then, four setups with convex lenses and concave mirrors were designed, enabling the study of the clues, and in the main activity, the students practiced each cue on the setups. Their experiences in the main activity were acquired through written reports, student observations, and interviews. Following the activities, the students related their perceptual experiences to their prior knowledge of images. Additionally, the students were questioned regarding their opinions on the use of five perceptual cues as image-learning strategies. The students found that the observation of binocular parallax in a lens or mirror represents a real image. They identified the relative positions of real and virtual images and their objects with the help of monocular parallaxes. They also connected their understanding of optics to the perceptual cues that real images appeared in front of mirrors and on the opposite side of the object in lenses, but virtual images appeared behind mirrors and on the object side of lenses. Conclusions were suggested for optics instructions.
Human body and physics: combined use of simulations and hands-on experiments to explain the quadricep muscle exercise
Authors: Mohottala Hashini , Althani Basim , Higgins Brent 
Published: August 2023

Abstract
We report the combined use of simulations and hands-on activities in a physics course designed to teach mechanics and the human body. Most students in the class are majoring in physical therapy or sports medicine. Although demonstrations, animations, and visual aids can tremendously help in teaching a course like this, we have access only to a few due to the novelty of the course. Therefore, to demonstrate the physics behind a physical therapy used to exercise the quadriceps muscle, we built a prototype that follows the function of a human knee. There we applied a force to the lower part of the leg (ankle area) and tracked the resultant force transferred into the quadriceps muscle. While this hands-on activity help students understand how torque balanced the system’s static equilibrium, the simulation we developed using JavaScript shows how the equilibrium is held even when the leg is moving. The simulation creates a unique, user-friendly atmosphere and invites students to try it by altering the parameters and modifying the program.
OH density, flux and loss probability measurements in a room temperature atmospheric pressure surface discharge by microscopic laser induced fluorescence
Authors: Wang Jianan , Bruggeman Peter J 
Published: August 2023

Abstract
Many applications involving atmospheric pressure plasma-substrate interactions are enabled by the large fluxes of short-lived reactive species such as OH radicals to the substrate, nonetheless, the accurate measurement of radical densities and fluxes at substrates at atmospheric pressure has received little attention to date, particularly for surface ionization waves. We report the measurement of the OH density distribution in a surface discharge on a fused silica (quartz) substrate generated by an impinging atmospheric pressure plasma jet in dry and humid helium. The OH density is measured by microscopic laser induced fluorescence with a spatial resolution of 10 µm in the direction perpendicular to the quartz substrate. The measured OH diffusive flux varied for the investigated experimental conditions by almost three orders of magnitude and had a maximum value of 1.7 × 1015 cm−2 s−1. The corresponding surface loss probability of OH on the quartz surface was determined to be ∼0.01. The high spatial resolution was required to accurately resolve the near surface gradient of OH radicals.
Performance of high-temperature superconducting REBCO coated conductors under synchrotron irradiation for future circular colliders
Authors: Krkotić Patrick , Traver Oriol , Tagdulang Nikki , Calatroni Sergio , Manuel O’Callaghan Juan , Pont Montse 
Published: August 2023

Abstract
The influence of medium-to-high energy synchrotron radiation (SR) (≈10–100 keV) produced by the ALBA Synchrotron Light Source on state-of-the-art REBCO coated conductors (CCs) has been studied to assess the feasibility of using high-temperature superconductors for the beam screen of future circular colliders. Long-term irradiation studies were conducted with ex-situ surface resistance testing by using a dielectric resonator. In addition, a cryogenic test system was established for in-situ measurements of the critical temperature and surface impedance of REBCO-CCs during synchrotron irradiation, with intensities similar to or above those generated by proton beams circulating in the vacuum chamber in the future circular collider hadron–hadron design. It is shown that the SR impact does not introduce any macroscopic defects that permanently alter the critical temperature or surface impedance of REBCO-CCs. However, the most significant effect of SR is a transient increase in the REBCO’s surface impedance. This effect is likely caused by heat, as the material returns to its original impedance values once the radiation exposure stops. The correlation between the time structure of the SR and the possibility of suppressing the Cooper pairing mechanism is also discussed.
Dynamic behavior of skyrmion collision: spiral and breath
Authors: Shi Shengbin , Zhao Yunhong , Sun Jiajun , Hou Xu , Zhou Haomiao , Wang Jie 
Published: August 2023

Abstract
A magnetic skyrmion is a particle-like topological soliton, which is an ideal candidate for developing high-density storage and logic devices due to its nonvolatility and tunability. In view of the particle motion characteristics of skyrmion, different skyrmions in a material inevitably interact in the form of short-range repulsion and long-range attraction. In this work, the dynamic characteristics of skyrmion collision in a ferromagnetic Co thin film are investigated by using micromagnetic simulations. It is found that the dynamic behavior of skyrmion after collision is highly dependent on the size of the strip, the initial velocity of skyrmion and magnetic damping constant. For the collision of two skyrmions, when the strip width exceeds the critical value, the skyrmions form a pair and rotate counterclockwise in the form of spiral and breath. It is interesting that the rotation and breath of skyrmions keep the same periodicity under the negligible damping, and the frequency increases with the increase of the initial velocity of skyrmion. Further, the collision of a system of three skyrmions reveals that they interact in pairs to form closed periodic trajectories. The results of the present work not only give an insight into the multi-skyrmion dynamics, but also provide guidance for the development of spintronic devices based on multi-skyrmion motion.
The Hawking energy in a perturbed Friedmann-Lemaître universe
Authors: Stock Dennis , Di Dio Enea , Durrer Ruth 
Published: August 2023

AbstractHawking's quasi-local energy definition quantifies the energy enclosed by a spacelike 2-sphere in terms of the amount of lightbending on the sphere caused by the energy distribution inside the sphere. This paper establishes for the first time a direct connection between the formal mathematical definition of a quasi-local energy and observations, in the context of cosmological perturbation theory. This is achieved by studying the Hawking Energy of spherical sections of the past lightcone of a cosmic observer in a perturbed Friedmann-Lemaître spacetime. We express the Hawking Energy in terms of gauge-invariant perturbation variables and comment on the cosmic observables needed to in principle measure it. We then calculate its angular power spectrum and interpret its contributions.