bluuebunny/crossref_metadata_2025_split huggingface dataset:
SnSe2 thermal conductivity from optothermal Raman and Stokes/anti-Stokes thermometry
Authors: Vallin Micah P , Karkee Rijan , Kucinski Theresa M , Zhao Huan , Htoon Han , Lee Chanho , Martinez Ramon M , Fensin Saryu J , Zhang Richard Z , Pettes Michael T 
Published: December 2024

Abstract
The optothermal Raman method is useful in determining the in-plane thermal conductivity of two-dimensional (2D) materials that are either suspended or supported on a substrate. We compare this method with the Stokes/anti-Stokes scattering thermometry method, which can play a role in both calibration of Raman peak positions as well as extraction of the local phonon temperature. This work demonstrates that the Stokes/anti-Stokes intensity ratio plays an important role in determining the in-plane thermal conductivity of 2D tin diselenide (SnSe2) dry-transferred onto a polished copper (Cu) substrate. The statistically-averaged thermal conductivity of the 108 ± 24 nm-thick SnSe2 yielded 5.4 ± 3.5 Wm−1 K−1 for the optothermal Raman method, and 2.40 ± 0.81 Wm−1 K−1 for the Stokes/anti-Stokes thermometry method, indicating that the Stokes/anti-Stokes thermometry method to calculate the thermal conductivity of a material can simultaneously increase both precision and accuracy. The uncertainty value was also lowered by a factor of 1.9 from the traditional optothermal Raman method to the Stokes/anti-Stokes thermometry method. The low in-plane thermal conductivity of 2D SnSe2, 1.3–2.9 times lower than bulk, is useful for applications in thermal and electrical energy conversion and thermoelectric devices.
Displaced volume versus submerged volume in the floating of a solid
Authors: Landi Salmon 
Published: December 2024

Abstract
This paper describes a new theoretical approach accompanied by experiments that demonstrate that the volume of the displaced fluid cannot be used to calculate the magnitude of the buoyant force when a solid object is floated in a container of only slightly larger cross-section than the object. It is important to emphasize that the discussions conducted here are accessible to high school and first-year university physics students because the concept of hydrostatic pressure and easily understood geometric considerations are applied.
A simple algebraic derivation of the equation for a line of best fit
Authors: Bissell J J 
Published: December 2024

Abstract
We present a simple algebraic derivation of the equation for a line of best fit. Unlike conventional derivations, which require multi-variable calculus, our argument relies on elementary algebra alone, and avoids more advanced notation (such as the sigma summation symbol) by exploiting routine data averages. In this way, our approach demystifies the process of computing a linear regression, and is likely to be of interest to students and instructors alike. We illustrate the main results with a worked example taken from an introductory physics context.
Compressibility of liquids and hydrostatic pressure
Authors: Koumaras Panagiotis , Koumara Anna 
Published: December 2024

Abstract
In this study, we first identify several misconceptions regarding the concept of hydrostatic pressure, as revealed through interviews with 27 secondary Physics teachers. These misconceptions are primarily linked to the assumption that liquids are incompressible. The objective of this research is to enhance teachers’ understanding by illustrating the limitations of the incompressible liquid model. As part of a three-hour instructional intervention designed for the interviewed teachers, we introduced the relationship between hydrostatic pressure, present at any point within a liquid, and the compression or deformation of the liquid’s molecules. The responses from the participating teachers suggest that this clarification effectively addressed the previously noted misunderstandings.
From pages to practice: improving reading comprehension and learning strategies through physics learning
Authors: De Ruyt Pablo , Pulgar Javier , Sánchez Iván , Herrera Edith 
Published: December 2024

Abstract
The study presents the effects of an educational intervention designed in the physics and Spanish classroom to encourage reading comprehension and learning strategies for meaningful learning. The intervention includes the reading of popular science books and group-level activities for solving a sequence of physics questions, conducted over an academic semester (2022) in a sample of 9th and 10th grade students from a secondary school in Chile. The study features a pre-experimental design with pre and post-tests to measure reading comprehension, learning strategies, student working networks during the intervention, and academic performance. Statistical comparisons show significant changes in reading comprehension, and improvements in learning strategies consistent with a transition towards strategic and meaningful learning orientations. Analysis of the collaboration networks allows us to understand these changes from a relational perspective, characterising subgroups and their development. These findings highlight the importance of reading exercises and group-level activities for human development, while social interactions offer alternative insights to understand the classroom experience.
Effect of the oblique incidence of radiation beams on emerging radiation behind lead and concrete shields: a multilayer method for dose transmission calculations
Authors: González-López Antonio 
Published: December 2024

Abstract

Objective. For calculating shielding in x-ray rooms, it is often assumed that the beams impinge perpendicularly on the protective barriers. This is not always true, but this premise simplifies the calculations and enhances protection by being a conservative calculation. In this work, a method for calculating radiation transmission through planar shielding that considers the obliquity of the incident beam is presented. Approach. The output of the method produces energy spectra according to the direction of radiation impinging on the shielding. Four angles of incidence on the barrier are considered, along with monoenergetic pencil beams with energies ranging from 10 to 150 keV and two materials: lead and concrete. The direction of emerging photons is discretized into 49 different direction vectors. Monte Carlo calculations are performed for thicknesses of 0.1, 0.5, and 1.0 mm of lead, and 1, 5, 10, and 15 cm of concrete. Additionally, a multilayer iterative method is implemented for calculating attenuation of other thicknesses. Main results. The distribution of radiant energy according to the coordinates of its directional vector illustrates the effect of the obliquity of the incidence and the significance of the shielding material employed. In the case of concrete, the dispersion of radiation away from the original direction of incidence is much more pronounced than in the case of lead at energies below its K-edge. The multilayer iterative method provides highly accurate values of transmitted radiant energy in both monoenergetic and polyenergetic beams, for both lead and concrete, across the various studied incidence directions. Significance. Considering the direction of the photons reaching a shield and the direction of the photons passing through it allows multilayer composite shielding calculations to closely approximate the calculation made for the composite shielding.
An adaptive learning method for long-term gesture recognition based on surface electromyography
Authors: Li Yurong , Lin Xiaofeng , Lin Heng , Zheng Nan 
Published: December 2024

Abstract

Objective. The surface electromyography (EMG) signal reflects the user’s intended actions and has become the important signal source for human-computer interaction. However, classification models trained on EMG signals from the same day cannot be applied for different days due to the time-varying characteristics of the EMG signal and the influence of electrodes shift caused by device wearing for different days, which hinders the application of commercial prosthetics. This type of gesture recognition for different days is usually referred to as long-term gesture recognition. Approach. To address this issue, we propose a long-term gesture recognition method by optimizing feature extraction, dimensionality reduction, and classification model calibration in EMG signal recognition. Our method extracts differential common spatial patterns features and then conduct dimensionality reduction with non-negative matrix factorization, effectively reducing the influence of the non-stationarity of the EMG signals. Based on clustering and classification self-training scheme, we select samples with high confidence from unlabeled samples to adaptively updates the model before daily formal use. Main results. We verify the feasibility of our method on a dataset consisting of 30 d of gesture data. The proposed gesture recognition scheme achieves accuracy over 90%, similar to the performance of daily calibration with labeled data. However, our method needs only one repetition of unlabeled gestures samples to update the classification model before daily formal use. Significance. From the results we can conclude that the proposed method can not only ensure superior performance, but also greatly facilitate the daily use, which is especially suitable for long-term application.
Study on hollow cathode discharge mode with high flow rate
Authors: Yang Yitao , Wu Zhiwen , Huang Tiankun 
Published: December 2024

Abstract
Hall and ion propulsion systems at power levels of ten kilowatts or higher are in development or application stages in recent years, yet research on the operational characteristics of corresponding hollow cathodes remains incomplete. This study conducts experimental research using a hollow cathode with a rated condition of 15 sccm of krypton gas and 10 A of current. By supplying a larger flow rate, the study expands the range of discharge currents to investigate changes in the discharge modes. The plume plasma characteristics and spatial distributions under various conditions were measured using a Langmuir single probe mounted on a planar two-dimensional displacement platform. The experimental results indicate that at krypton flow rates of 25 sccm and 30 sccm, as the current increases, the anode voltage and discharge oscillations increase at first but decrease later. The discharge mode transitions from low-current spot mode to plume mode, and then back to spot mode at high current. The increase in anode voltage and oscillations during the first transition phase is gradual and continuous, while the decrease during the second transition phase is abrupt. Conditions of 10 A, 12.5 A, and 20 A were selected to represent these three modes for single-probe plume spatial diagnostics. The results indicate that in the high-current spot mode, the axial potential gradient is significantly reduced compared to the radial gradient, and the cathode plasma plume is more collimated. This study shows that at high flow rates, hollow cathodes may exhibit nonlinear impedance and undergo multiple discharge mode transitions, with each transition phase displaying distinct characteristics.
Nucleation kinetics and virtual melting in shear-induced structural transitions
Authors: Li Wei , Peng Yi , Still Tim , Yodh A G , Han Yilong 
Published: December 2024

Abstract
Large shear deformations can induce structural changes within crystals, yet the microscopic kinetics underlying these transformations are difficult for experimental observation and theoretical understanding. Here, we drive shear-induced structural transitions from square (

◻

) lattices to triangular (

△

) lattices in thin-film colloidal crystals and directly observe the accompanying kinetics with single-particle resolution inside the bulk crystal. When the oscillatory shear strain amplitude

0.1
⩽

γ
m

<
0.4

,

△

-lattice nuclei are surrounded by a liquid layer throughout their growth due to localized shear strain at the interface. Such virtual melting at crystalline interface has been predicted in theory and simulation, but have not been observed in experiment. The mean liquid layer thickness is proportional to the shear which can be explained by the Lindemann melting criterion. This provides an alternative explanation on virtual melting.
Analysis, modeling and design of piezoelectric-capacitive hybrid micromachined ultrasonic transducer
Authors: Wang Yan , Lv Ning , He Leming , Ren Junyan 
Published: December 2024

Abstract
This paper proposes a spring-mass-damper model for a piezoelectric-capacitive hybrid micromechanical ultrasonic transducer (HMUT) in immersion. Based on this model, a dual-force actuation mode is identified, where piezoelectric micromachined ultrasonic transducer (PMUT) and capacitive micromachined ultrasonic transducer (CMUT) are strongly coupled to achieve enhanced sensitivity. In order to design HMUT efficiently, an electro-mechanical-acoustical equivalent circuit model (ECM) is constructed and then the round-trip gain is calculated to demonstrate its pulse-echo response. The ECM calculations results align with those of finite element model simulations, showing a relative deviation less than 4%. In the design cases, the transmit sensitivity of HMUT is twice that of PMUT and more than five times that of CMUT. The receive sensitivity of HMUT is 1% lower than that of CMUT, but an order of magnitude larger than that of PMUT. The round-trip gain of the HMUT is at least 24.9 dB higher than that of PMUT and 14.1 dB higher than that of CMUT. These results demonstrate the potential of HMUT in surpassing bulk piezoelectric ultrasonic transducers in pulse-echo imaging. Furthermore, the impact of cell pitch on the pulse-echo response of HMUT arrays is characterize.
Recent developments in applications of G-CuO nanocomposites for photocatalytic dye removal
Authors: Mehmood Arslan , Sandhu Zeshan Ali , Iqbal Muhammad Jawad , Manzoor Ayesha , Elahi Maha , Liyaqat Samreen , Nadeem Iqra , Zainab Syeda Ammer , Bibi Amina 
Published: December 2024

Abstract
The widespread application of synthetic dyes across industries poses significant environmental problems, particularly concerning with degradation of water quality. Concerning the possible solutions, copper oxide (CuO) considered as a feasible candidate. CuO a p-type heterogeneous semiconductor with a bandgap of 1.2–2.71 eV, It is a reasonable choice and widely studied photocatalyst for addressing such challenges. The functionality of CuO deteriorated, when the wavelength exceeded the UV–visible region. In this manner difficulties associated with reproducibility and reusability, as well as rapid electron–hole recombination, prevent the widespread application of this technology. In an attempt to eliminate this defect, researchers have been investigating strategies to activate CuO under visible light, with one promising approach being carbon nanomaterials such as graphene to form carbon-CuO composites. The unique properties of graphene, i.e., its higher surface area and excellent electron mobility, make it a remarkable candidate for the enhancement of CuO photoactivity. This study highlighted the recent progress in the synthesis of graphene-based CuO photocatalysts, with the main characteristic of extending the light absorption capacity of CuO into the visible spectrum. It reveals achievements in material innovations and applications, with a focus on photocatalytic. It has been observed from the documented studies, catalysis is considered as next generation emerging field for the researcher.
On nonclassical symmetries, Painlevé analysis and soliton solutions of three-coupled korteweg–de vries (KdV) system
Authors: Sharmila  , Gupta Rajesh Kumar 
Published: December 2024

Abstract
The three coupled KdV system is investigated for exact solutions and Painlevé analysis. Exact solutions are examined through nonclassical symmetries via Bluman and Cole approach. Derived symmetries are generalizations of earlier obtained symmetries of the considered system. There is power series solution of the reduced ODEs of the examined system. Assuming the solutions in terms of Jacobi elliptic functions, some new soliton solutions of the system under consideration are obtained. These solutions are two-singular soliton, three-singular soliton, multi-soliton, multi-singular soliton, combined soliton, bright solion, dark soliton, and bell shaped soliton solutions. Further, graphical depiction of the exact solutions to the governing system. Using Kruskals method and symbolic software Maple, it is verified that the system has Painlevé property that represents integrability of the governing system.
Ultrawideband low RCS metasurface based on optimized multielement phase cancellation and diffusion reflection
Authors: Zhang Haonan , Guo Qingxin , Zhao Huachen , Li Zengrui 
Published: December 2024

Abstract
A metasurface (MTS) based on optimized multielement phase cancellation and diffusion reflection is proposed for ultrawideband radar cross section reduction (RCSR). The unit cell of the MTS consists of a rectangular patch on the top layer, a cross slot in the center layer, and a ground plane on the bottom layer. The periodic array of the unit cells converts the linear polarization wave to its cross-polarization in the band of 5.17–7.74 GHz. To extend the bandwidth of RCSR, the height and the arrangement of the proposed unit cells and their mirror unit cells are optimized through the particle swarm optimization algorithm to achieve optimized multielement phase cancellation and diffusion reflection. The simulation and measurement results show that the proposed MTS achieves 10 dB RCSR from 5.8–70.6 GHz, with high angular stability and polarization insensitivity performance.
Enhancing Gaussian quantum metrology with position-momentum correlations
Authors: Porto João C P , Marinho Lucas S , Dieguez Pedro R , da Paz Irismar G , Vieira Carlos H S 
Published: December 2024

Abstract
Quantum metrology offers significant improvements in several quantum technologies. In this work, we propose a Gaussian quantum metrology protocol assisted by initial position-momentum correlations (PM). We employ a correlated Gaussian wave packet as a probe to examine the dynamics of Quantum Fisher Information (QFI) and purity based on PM correlations to demonstrate how to estimate the PM correlations and, more importantly, to unlock its potential applications such as a resource to enhance quantum thermometry. In the low-temperature regime, we find an improvement in the thermometry of the surrounding environment when the original system exhibits a non-null initial correlation (correlated Gaussian state). In addition, we explore the connection between the loss of purity and the gain in QFI during the process of estimating the effective environment coupling and its effective temperature.
Slow-moving ground target imaging using vortex synthetic aperture radar
Authors: Fu Ziyu , Li Minchao , Cui Lizhen , Li Chenlu , Du Yongxing , Li Baoshan 
Published: December 2024

Abstract
A vortex synthetic aperture radar (SAR) can obtain more target information when combined with orbital angular momentum (OAM). However, ground-moving targets can cause image defocusing owing to their azimuthal velocity component, and imaging position offset issues owing to their range velocity component. However, additional information regarding moving targets can be acquired for analysis using vortex SAR. This study first established an imaging model to extract moving target information from vortex echo signals. Subsequently, the target Doppler parameters were estimated, and an improved range-Doppler algorithm was applied to compensate for the Bessel and azimuthal phase terms. A new azimuth-matched filter was designed based on the Doppler parameters to achieve focused imaging of moving targets. The simulation results verified the effectiveness of the proposed algorithm and its performance was compared with that of plane-wave SAR. Vortex SAR offered better target quality parameters and azimuth resolution for the same synthetic aperture length. The proposed algorithm effectively improved the azimuthal imaging of moving targets in low-to-moderate OAM modes.
The relationship between the spatial heterogeneity of the microstructure and the glass-forming ability of Al85Ni10Fe5 metallic glass
Authors: Song Shengjia , Yao Xiuwei , Sun Minhua 
Published: December 2024

Abstract
Spatial heterogeneity of the microstructure is an inherent characteristic of metallic glasses, which significantly influences their glass-forming ability (GFA) and thermal stability. In this study, we employ molecular dynamics simulations to investigate the evolution of spatial heterogeneity in the microstructure of the Al85Ni10Fe5 alloy during the glass transition process. Our results reveal that the Al85Ni10Fe5 metallic glass exhibits much higher spatial heterogeneity in terms of five-fold symmetry compared to the Al85Ni15 alloy. Furthermore, the spatial heterogeneity of the five-fold symmetry increases more dramatically during the cooling process in the Al85Ni10Fe5 system, while the spatial heterogeneity of the four-fold symmetry, which is associated with the crystalline phase, is lower in Al85Ni10Fe5 than in Al85Ni15. Interestingly, the spatial heterogeneity of the four-fold symmetry in Al85Ni10Fe5 first increases with decreasing temperature and then rapidly decreases near the glass transition temperature. These structural characteristics, which benefit the formation of higher five-fold symmetric clusters and their spatial aggregation, thus suppressing the growth of the crystalline structure in the liquid, contribute to the larger GFA of the Al85Ni10Fe5 alloy compared to the Al85Ni15 alloy. Our findings provide valuable insights into understanding the glass-forming ability of Al-based metallic glasses.
Physicochemical properties of CF3OCF = CF2 in high-voltage switchgear: part 1. Decomposition characteristics and thermodynamic parameters
Authors: Cui Zhaoxuan , Lin Xin , Geng Zhenxin , Xia Yalong , Xu Jianyuan 
Published: December 2024

Abstract
Recently, perfluoromethyl vinyl ether (CF3OCF = CF2) has been proposed to have the potential to replace SF6, but its arc-extinguishing ability is still unknown. To provide the necessary basic parameters for further study of arc extinguishing characteristics, this series of papers focuses on the physical and chemical properties of CF3OCF = CF2 arc plasma. The research content of this paper is decomposition characteristics and thermodynamic parameters. The geometric configuration, rotational inertia, and vibration frequency characteristics of CF3OCF = CF2 and its decomposition products were obtained at the B3LYP/6–311G(d,p) level. The energy of each particle was calculated at the CCSD(T)/cc-pVTZ level. The most likely decomposition path was CF3OCF = CF2→CF3+CF2CFO→CF2+CFO. The equilibrium compositions of arc plasma were calculated by the mass action law model. The main components of pure CF3OCF = CF2 after arc were C3F8, C3F6, C2F6, CF4, and CO. When CO2 was mixed in CF3OCF = CF2, with the increase of CO2 content, the main components after arc gradually became CF2O, CF4, CO2, and CO. The thermodynamic parameters such as density, specific enthalpy, and specific heat at constant pressure were obtained by thermodynamic relationship. Through ρC

p
and ρh, it can be inferred that the radial heat transfer capacity of CF3OCF = CF2 is not as good as SF6, but the energy dissipation capacity of axial heat convection is stronger than SF6, and the arc presents the characteristics of large radius and long length.