bluuebunny/crossref_metadata_2025_split huggingface dataset:
Statistical RTA simulations of atomic data for astrophysical opacity modeling in the context of kilonova emission
Authors: Carvajal Gallego H , Pain J-C , Godefroid M , Palmeri P , Quinet P 
Published: January 2024

Abstract
When considering some complex lanthanide ions characterized by a half-filled 4f subshell, the atomic structure Hamiltonian matrix sizes are so large that their diagonalization is challenging and therefore the atomic data of these ions are only used to compute the expansion opacity of a kilonova with difficulty. To avoid this problem, we propose a statistical simulation method to compute kilonova expansion opacities based on the resolved transition array (RTA) method of Bauche et al (1991 Phys. Rev. A 44 5707). The atomic structure relativistic Hartree–Fock (HFR) method has been employed to compute the radial integrals necessary for our statistical RTA simulations where the atomic data are randomly drawn using their corresponding statistical distributions and to determine the exact expansion opacities where the atomic data are obtained by the diagonalization of the Hamiltonian matrix. The statistical RTA simulations carried out for two specific ions, i.e. Sm VIII and Eu VI, for which it is still possible to diagonalize the Hamiltonian matrix, reproduce well the expansion opacities computed using HFR atomic data. Based on this good agreements, the statistical RTA method was used to compute the expansion opacity of Dy VIII, which is determined through diagonalization with difficulty. The proposed statistical RTA simulation method allows the computation of reliable astrophysical expansion opacities which are of paramount importance for kilonova light curve modeling and spectral analysis.
On the magnetization of the 120° order of the spin-1/2 triangular lattice Heisenberg model: a DMRG revisited
Authors: Huang Jiale , Qian Xiangjian , Qin Mingpu 
Published: January 2024

Abstract
We revisit the issue about the magnetization of the 120° order in the spin-1/2 triangular lattice Heisenberg model with density matrix renormalization group (DMRG). The accurate determination of the magnetization of this model is challenging for numerical methods and its value exhibits substantial disparities across various methods. We perform a large-scale DMRG calculation of this model by employing bond dimension as large as

D
=
24
000

and by studying the system with width as large as

L

y

=
12

. With careful extrapolation with truncation error and suitable finite size scaling, we give a conservative estimation of the magnetization as

M
0

=
0.208
(
8
)

. The ground state energy per site we obtain is

E

g

=
−
0.5503
(
8
)

. Our results provide valuable benchmark values for the development of new methods in the future.
Defects in epitaxial 4H-SiC revealed by exciton recombination
Authors: Migliore Francesca , Cannas Marco , Mario Gelardi Franco , Vecchio Daniele , Brischetto Andrea , Agnello Simonpietro 
Published: January 2024

Abstract
In this work, we conducted an analysis of 4H-SiC epitaxial layer grown on two distinct 4H-SiC substrates (both 6 inches in diameter) using non-invasive techniques such as micro-Raman spectroscopy, steady-state absorption spectroscopy and time-resolved photoluminescence spectroscopy. We have shown that despite the doping homogeneity, confirmed by micro-Raman and steady-state absorption spectroscopy, the carrier lifetime, assessed by monitoring the excitonic band at 3.2 eV by time-resolved photoluminescence spectroscopy, depends on the position on the wafer. This variability is attributed to the presence of defects, such as impurities or point defects, which are not uniformly distributed on the epitaxial layer and that, in addition to extended defects, affect the charge carrier recombination. Additionally, it is found that interactions with the underlying substrate could contribute to these effects as evidenced in regions of the substrate characterized by differences of doping.
Intelligent fault diagnosis of double-aligned domain adaptation based on multi-structure fusion and multi-attention mechanism
Authors: Shang Zhiwu , Wu Changchao , Pan Cailu , Li Wanxiang , Cheng Hongchuan 
Published: January 2024

Abstract
Currently, most fault diagnosis methods based on domain adaptation (DA) reduce the distribution discrepancy between the source and target domains by aligning their high-dimensional features, but do not consider the impact of the source domain decision boundary on the distribution of the target domain, which leads to slow convergence and poor generalization. Aiming at the above-mentioned issues, this paper proposes a double-aligned DA deep transfer model (MSADA) based on multi-structure fusion and multi-attention mechanism. Firstly, a multi-structure fusion network with Inception module is constructed to increase the information capacity in the extracted features and enhance the representation of deep features. Then, the multi-attention mechanism is embedded into different convolutional channels separately to learn globally and locally important information and reduce the influence of the source domain decision boundary on the target domain distribution. Finally, the multi-kernel maximum mean discrepancy and KL divergence are combined as a new double-aligned distribution discrepancy metric to align the samples and probability distributions of the source domain and the target domain, respectively. At the same time, a dynamic adaptive factor is designed to adjust the contribution of the two types of distributions, thus effectively improving the training efficiency and the robustness of the model. Through the validation analysis of two rolling bearing dataset cases, the proposed MSADA has better cross-domain diagnostic performance than other DA methods.
A water track laser Doppler velocimeter for use in underwater navigation
Authors: Huang Rong , Wang Qi , Xiang Zhiyi , Nie Xiaoming , Zhou Jian , Luo Hui 
Published: January 2024

Abstract
Doppler velocity log (DVL) is usually employed to suppress the divergency of the Strapdown Inertial Navigation System (SINS) in underwater navigation, which is not concealable due to high transmittance for acoustic wave in the water. To conduct underwater navigation task with high concealment, a differential laser Doppler velocimeter (LDV) working at water track mode is integrated with SINS in this paper. The developed LDV measures the advance velocity of the underwater carrier with respect to the surrounding water in underwater navigation scenario with advantages of high concealment, high real-time performance, high update rate, light weight, and small dimension. A dynamic river test was conducted to validate the underwater navigation performance of SINS/LDV integrated system. The experimental results show that during the voyage of 4493s and 5271.8 m, the maximum horizontal positioning errors of the proposed SINS/LDV integrated underwater navigation system is 27.8 m and the relative position error is less than 0.6% with respect to total distance. Therefore, the water track LDV is practical to aid SINS in underwater navigation environment.
Conductivity enhancement of Ag nanowire ink by decorating in situ formed Ag particles under low-temperature sintering
Authors: Feng Junyan , Xing Bo , Xu Jiahao 
Published: January 2024

Abstract
Silver nanowires (AgNWs) have attractive applications in the fabrication of flexible electronics because of their adequate electrical conductivity, mechanical properties, and oxidation resistance. However, the film produced by AgNW ink needs to be sintered at temperatures above 200 °C to obtain high electrical conductivity, which is incompatible with commonly used flexible substrates such as paper or polymer materials. In this study, the AgNW network was decorated by in situ reduced Ag particles (AgPs) to improve the structural integrity and conductivity of the film. After sintering at 80 °C, the pores and voids within the AgNW network were filled with Ag particles smaller than 200 nm, and the porosity of the film was markedly reduced. The lowest resistivity value was 3.9 × 10–5 Ω cm after sintering at 100 °C, only 10.8% and 8.5% of the resistivity values of the films produced from AgNW and ion inks, respectively. During sintering, Ag nucleated on the surface of AgNWs, and its growth and agglomeration resulted in interconnections between the AgNWs and Ag particles. Thereafter, the bridging and filling effect of the Ag particles facilitated the formation of a compact and firm network, improving the film conductivity. The line film printed from the composite ink with 10 layers exhibited a low resistivity of 7.3 × 10–7 Ω·m. Even after 5000 bending cycles, the resistivity of the line only increased by 4.47 × 10–6 Ω·cm from the initial value. The composite ink reported in this study is a promising candidate for the low-cost printing of ultralow-power-consumption wearable electronic devices.
Three-dimensional ordered macroporous design of heterogeneous cobalt–iron phosphides as oxygen evolution electrocatalyst
Authors: Zhao Songan , Cao Weijin , Lu Lu , Tan Zhaoyang , Wang Yanji , Wu Lanlan , Li Jingde 
Published: January 2024

Abstract
Oxygen evolution reaction (OER) plays a key role in electrochemical conversion, which needs efficient and economical electrocatalyst to boost its kinetics for large-scale application. Herein, a bimetallic CoP/FeP2 heterostructure with a three-dimensional ordered macroporous structure (3DOM-CoP/FeP2) was synthesized as an OER catalyst to demonstrate a heterogeneous engineering induction strategy. By adjusting the electron distribution and producing a lot of active sites, the heterogeneous interface enhances catalytic performance. High specific surface area is provided by the 3DOM structure. Additionally, at the solid–gas-electrolyte threephase interface, the electrocatalytic reaction exhibits good mass transfer. In sit
u Raman spectroscopy characterization revealed that FeOOH and CoOOH reconstructed from CoP/FeP2 were the true OER active sites. Consequently, the 3DOM-CoP/FeP2 demonstrates superior OER activity with a low overpotentials of 300/420 mV at 10/100 mA cm–2 and meritorious OER durability. It also reveals promising performance as the overall water splitting anode.
Hardy inequalities for magnetic p-Laplacians
Authors: Cazacu Cristian , Krejčiřík David , Lam Nguyen , Laptev Ari 
Published: January 2024

AbstractWe establish improved Hardy inequalities for the magneticp-Laplacian due to adding nontrivial magnetic fields. We also prove that for Aharonov–Bohm magnetic fields the sharp constant in the Hardy inequality becomes strictly larger than in the case of a magnetic-freep-Laplacian. We also post some remarks with open problems.
Students’ scaling of axes when constructing qualitative graphs that represent a physics scenario
Authors: Condon Orlaith , Kelly T J , Power Stephen R , van Kampen Paul 
Published: January 2024

Abstract
We have studied how first-year university science students construct graphs based on hypothetical qualitative physics scenarios. We gave students a questionnaire that asked them to complete two Cartesian graphs in one of three different scenarios (a ball rolling down a track, a beaker being filled with water, the resistance between different points on a metal bar) given as a written piece of text accompanied by a diagram of a hypothetical experiment that included three evenly spaced points on the set-up. Two of the three points were also indicated on the position axis of the partially drawn graph. We found that students can find it hard to translate equal spatial intervals in the experiment to a line graph. We found that most students either did not explain why they put the third point on the graph where they did, or did not plot the point at all. Some students drew unequal intervals on the position axis to indicate unequal time or resistance intervals. The difficulties became more prevalent as the levels of abstraction increased. Our findings suggest that constructing a scale on a qualitative graph requires significant mental effort from the students.
Validating light phenomena conceptual assessment through the lens of classical test theory and item response theory frameworks
Authors: Santoso Purwoko Haryadi , Istiyono Edi , Haryanto  , Retnawati Heri 
Published: January 2024

Abstract
The light phenomena conceptual assessment (LPCA) is a conceptual survey of light phenomena that has been recently established by physics education research (PER) scholars. Studying the LPCA psychometric properties is imperative to inform its measurement validity to potential LPCA users as well as general educational researchers. Classical test theory (CTT) and item response theory (IRT) are two popular statistical frameworks that can be utilized to explore the LPCA measurement validity. To our knowledge, no PER studies have attempted to make a head-to-head comparison of these methods while validating the LPCA. This study is the first to delineate the LPCA measurement by statistically comparing CTT- and IRT-based analyses. The LPCA dataset was drawn from physics students from eight secondary schools presented by Ndihokubwayo and Uwamahoro (2020 Phys. Educ.
55 035009). Our results accomplish harmony between the CTT and IRT arguments to estimate the LPCA item performance and student ability probed by the LPCA. They support the idea that the LPCA may be used as an inventory for evaluating conceptual understanding of light phenomena from the low to high ability range of students, and even some LPCA items should be flagged based on CTT- and IRT-based validity arguments. Special considerations for further refinement related to the discriminating power of problematic LPCA items are discussed.
From caged compounds with isolated U atoms to frustrated magnets with 2- or 3-atom clusters: a review of Al-rich uranium aluminides with transition metals
Authors: Pasturel Mathieu , Pikul Adam 
Published: January 2024

Abstract
Crystal structures and physical properties of four families of Al-rich ternary uranium compounds with transition metals (TE) are reviewed, namely UTE
2Al20, UTE
2Al10, U6
TE
4Al43, and U3
TE
4Al12. The compounds can be described as consisting of 1 (isolated), 2 (dumbbells) or 3 (triangles) uranium atom clusters, surrounded (1–2–20, 1–2–10 and 6–4–43) or not (3–4–12) by large cages, which strongly influence their magnetic and related properties. Indeed, the ground states of the described systems evolve from Curie-like paramagnetism in the case of the phases with well-isolated, single U-atoms, to complex magnetic order or possible frustrated magnetism in the case of the systems with uranium triangles forming a breathing kagome lattice. We argue that the four families of uranium aluminides described in this review provide a unique opportunity to study magnetic interactions between U magnetic moments while gradually increasing the number of their nearest magnetic neighbors, and may also be helpful in understanding the fundamental origin of magnetic freezing phenomena.
Explicit model predictive control of magnetorheological suspension for all-terrain vehicles with road preview
Authors: Li Wei , Liang Huijun , Xia Dongbin , Fu Jie , Yu Miao 
Published: January 2024

Abstract
The integration of magnetorheological (MR) semi-active suspension systems in all-terrain vehicles (ATV) has garnered significant attention due to their ability to enhance damping performance and off-road capabilities. However, traditional control strategies result in poor control accuracy and limited vibration reduction effects when facing complex road excitations and impact disturbances. With technological advancements, enhanced vehicle environmental perception and road sensing capabilities have made it possible to implement model predictive control (MPC) for vehicle suspensions. Nevertheless, traditional MPC is limited in vehicle suspension applications due to its high computational complexity. To address these issues, this study introduces an explicit model predictive control based on road preview (EMPC-P). Firstly, road data obtained through a non-contact measurement method enables the system to perceive road excitation information in advance. Subsequently, a 7 Degree-of-Freedom (7-DOF) suspension model incorporating road excitations is constructed. By adhering to system constraints and employing a multiparameter optimization method, the control problem based on rolling optimization is transformed into an explicit polyhedral system. The offline precomputation of control state relations enhances the computational efficiency of the control system. Through this approach, the designed EMPC allows the vehicle suspension system to make optimal control decisions quickly and accurately in response to complex driving conditions, thus improving the damping effect of the system. Through a combined approach of simulation and experimental validation, the designed EMPC-P controller is compared with the Skyhook controller under preview and non-preview states, respectively. Empirical testing confirms that the EMPC-P exhibits superior damping effects, significantly improving vehicle ride comfort and handling stability.
Exploring the quantum vacuum via ultraintense laser-induced refraction of light
Authors: Wang J , Chen G Y , Lei B F , Jin S , Yang L Y , Gan L F , Zhou C T , Zhu S P , He X T , Qiao B 
Published: January 2024

Abstract
The rapid progress of ultraintense laser technology provides a novel route to explore the quantum vacuum effect in the laboratory. Here, we propose using oblique collisions between an ultraintense pump laser and an x-ray probe laser to experimentally identify the quantum vacuum effect, where the change of the refraction properties including the refraction angle of the probe laser is taken as a detectable signature. The theoretical basis of the proposed scheme are analyzed in details, where a reasonable estimation of the scheme is given. To verify the proposed scheme, a series of two-dimensional particle-in-cell (PIC) simulations, with the vacuum polarization effect self-consistently taken into account, are carried out.
On the complex solution of the Schrödinger equation with exponential potentials
Authors: Garcia Javier 
Published: January 2024

Abstract
We study the analytical solutions of the Schrödinger equation with a repulsive exponential potential λ
e
−r
, and with an exponential wall λ
e

r
, both with λ > 0. We show that the complex eigenenergies obtained for the latter tend either to those of the former, or to real rational numbers as λ → ∞ . In the light of these results, we explain the wrong resonance energies obtained in a previous application of the Riccati-Padé method to the Schrödinger equation with the repulsive exponential potential, and further study the convergence properties of this approach.
Effects of boron doping in InSe single crystals on optical limiting performance in the near-infrared region
Authors: Doğan Anıl , Pepe Yasemin , Bilgili Meliha Yağmur , Karatay Ahmet , Ertap Hüseyin , Karabulut Mevlüt , Elmali Ayhan 
Published: January 2024

Abstract
Identification of photonic materials with high infrared transmittance and high nonlinear optical coefficients is one of the main emphases in material science as a result of the rapid advancement in infrared photonics. In this study, undoped and B (boron) -doped InSe single crystals were grown by using the modified vertical Bridgman method, and their nonlinear optical properties were investigated to reveal their usability as an optical limiter in the near-infrared region. The decreasing band gap energies and increasing defect states were determined with increasing B concentration in InSe single crystals. The effect of the B concentration on the nonlinear absorption (NA) and optical limiting properties of the InSe single crystals was investigated via open aperture (OA) Z-scan experiments under ultrafast laser excitation at 1200 nm wavelength with 100 femtosecond pulse duration. Two-photon absorption (TPA) was the dominant NA mechanism at 1200 nm excitation wavelength in the femtosecond domain. The results revealed that the NA became stronger with increasing input intensity and increasing amount of B dopant atoms in the InSe single crystal. The observed enhanced NA can be attributed to two possible events (i) increasing input intensity induced more excited electrons which led to more contribution to NA through TPA and (ii) increasing B dopant atoms in InSe single crystal induced more defect states. The NA may be more enhanced with the contribution of these defect states related NA mechanisms. The high transparency and strong NA behavior at the near-infrared region make these single crystals exceptional potential candidates for developing various optoelectronics and filters at the near-infrared spectral region.
Enhancement of gravitational waves at Q-ball decay including non-linear density perturbations
Authors: Kawasaki Masahiro , Murai Kai 
Published: January 2024

Abstract
The existence of a stochastic gravitational wave background is indicated by the recent pulsar timing array (PTA) experiments.
We study the enhanced production of second-order gravitational waves from the scalar perturbations when the universe experiences a transition from the early matter-dominated era to the radiation-dominated era due to Q-ball decay.
We extend the analysis in previous work by including the frequency range where density perturbations go non-linear and find that the resultant gravitational wave spectrum can be consistent with that favored by the recent PTA experiment results.
A Novel Eccentricity Parameterization for Transit-only Models
Authors: Eastman Jason D. 
Published: January 2024

Abstract
We present a novel eccentricity parameterization for transit-only fits that allows us to efficiently sample the eccentricity and argument of periastron, while being able to generate a self-consistent model of a planet in a Keplerian orbit around its host star. With simulated fits of 330 randomly generated systems, we demonstrate that typical parameterizations often lead to inaccurate and overly precise determinations of the planetary eccentricity. However, our proposed parameterization allows us to accurately—and often precisely—recover the eccentricity for the simulated planetary systems with only transit data available.