物理最新文献

This study investigated the electrochemical characteristics of NdFeO₃ nanocomposite improved with added small quantity of MXene. The NdFeO₃/MXene was synthesized using a standard solve-thermal technique and analyzed using X-ray diffraction, Fourier Transform Infrared Spectroscopy, etc . The electrochemical efficiency of the composite was tested for supercapacitors (SCs). The compositive was investigated in 3 M KOH electrolytic solution where NdFeO₃/MXene was pasted on nickel foam and served as working electrode. CV revealed that NdFeO₃/MXene has reached the capacitance of 1148.12 F g⁻¹ (5 mV s⁻¹). GCD research revealed that NdFeO₃ nanoparticles along with NdFeO₃/MXene nanocomposite had capacitance values of 703.17 F g⁻¹ as well as 1315.06 F g⁻¹ at 1 A g⁻¹. The NdFeO₃/MXene indicated that greater E_d along with P_d is 17.99 Wh kg⁻¹, 510 W kg⁻¹. After 4700 cycles, the material containing NdFeO₃/MXene nanocomposite remained stable. Chrono test confirmed high stability of composite material. The electrochemical investigation of generated NdFeO₃ nanocomposite shown that addition of MXene caused in a hybrid capacitive nature, as the suggested NdFeO₃/MXene can be used as SCs electrodes in energy storage. The NdFeO₃/MXene nanocomposite exhibits excellent electrochemical performance as compared to previously reported perovskite–MXene, due to its optimized hetero-interface, greater electrical conductivity, as well as abundant redox active site. The incorporation of NdFeO₃ enhanced pseudo-capacitive behavior, while MXene provides quick electron transport pathway, resulting in higher specific capacitance, outstanding rate capability, and cyclic stability to earlier perovskite–MXene.

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This study presents the first systematic molecular dynamics investigation of polyethylene (PE) and polypropylene (PP) nanocomposites reinforced with randomly functionalized single-walled carbon nanotubes (SWCNTs). Armchair (8,8) and zigzag (14,0) SWCNTs with nearly identical diameters (10 Å) were functionalized with hydrogen and fluorine atoms at 5–25% functionalization levels and incorporated into polymer matrices at 10% volume fraction. Representative volume elements (RVEs) were subjected to tensile loading simulations up to failure using Tersoff and Dreiding potentials to quantify Young’s modulus, maximum stress, failure strain, strain energy, and toughness. Results demonstrate that increasing functionalization consistently reduces mechanical properties across all systems, with Young’s modulus decreasing from range of 60–70 GPa to the range of 40–50 GPa and maximum stress declining from around 11 GPa. Zigzag SWCNTs generally outperformed armchair configurations in stiffness and strength, while armchair SWCNTs exhibited superior strain capacity. PE-based nanocomposites showed slightly better performance than PP-based systems for certain properties. Although CNT–polymer nanocomposites have been widely studied, a systematic comparison of randomly applied hydrogen and fluorine functionalization in both PE and PP matrices has not been conducted before. Comprehensive comparative analysis between functionalization types, polymer matrices, and nanotube chiralities provides essential design guidelines for optimizing nanocomposite performance in various applications.

The Lee–Wick pseudo-quantum electrodynamics in the presence of a Chern–Simons term is studied in this paper. The paper starts with a non-local lagrangian density that sets the pseudo-Lee–Wick electrodynamics defined on a (1+2) space-time added to a non-local Chern–Simons topological term. Thus, we obtain the Lee–Wick–Chern–Simons pseudo-electrodynamics as a most complete gauge invariant model that provides a light mass associated with the Chern–Simons parameter, and also includes a Lee–Wick heavy mass. We investigate classical aspects as the potential energy for the interaction of static charges through the gauge propagator. The causality of theory is discussed through the retarded Green function in the coordinate space. The gauge field of the Lee–Wick–Chern–Simons pseudo-electrodynamics is minimally coupled to the fermions sector that includes new degree of freedoms, as a Lee–Wick heavy fermion partner of the electron. The perturbative approach for the theory is presented via effective action in which we obtain the Ward identities. We study the quantum corrections at one loop, as the electron self-energy, the vacuum polarization, and the 3-vertex. We show that the Lee–Wick mass has a fundamental role in these results, where it works like a natural regulator of the ultraviolet divergences. The (g-2) factor for the electron is obtained as function of the LW mass, and of the CS parameter. Through the optical theorem, the Lee–Wick–Chern–Simons pseudo-electrodynamics is unitary at the tree level.

We present a comprehensive spectral study of the supersoft X-ray source RX J0925.7-4758 using six observations from ASCA, Chandra, XMM-Newton and NICER, spanning 25 years. Our primary objective is to identify a robust non-local thermodynamic equilibrium (NLTE) spectral model that consistently fits the continuum emission across all data sets. A systematic fitting procedure revealed that only a pure-hydrogen NLTE model with effective gravity (log g = 7) could achieve acceptable fits for all observations. The composite model incorporates photoelectric absorption, interstellar medium (ISM) absorption with non-solar abundances and discrete absorption edges at known threshold energies. The effective temperatures are found to be of the order of (sim !!! 10^{5}) K and the luminosities are estimated to be (sim !! 10^{41} mathrm {erg, s}^{-1}), suggesting that the emission arises from a hot accretion disk around a white dwarf undergoing steady hydrogen burning. Additionally, we examine the relative strengths of the bound-free absorption edges in all six observations. While consistent trends are seen in earlier missions, the NICER data show variability in edge dominance, likely due to the instrumental or calibration differences. Although the continuum spectra can be modelled satisfactorily, high-resolution grating spectra from XMM-Newton reveal complex line features, including P Cygni profiles, which are not reproduced by static atmosphere models. This highlights the need for future NLTE+wind models to interpret these data more completely. Our study lays a foundation for such future analyses of high-resolution grating spectra of supersoft X-ray sources.

A novel functionalized quinoline derivative, (E)-N’-(7,7-dimethyl-2-oxo-4-phenyl-2,3,4,6,7,8-hexahydroquinazole-5(1 H)-ylidene) isonicotinohydrazide, is developed and produced for potential therapeutic and nonlinear optical (NLO) uses. The structural elucidation is supported by FT-IR, UV-vis, NMR, and mass spectrometry, and the results are supported by DFT calculations at the B3LYP/6-31G(d, p) level. AIM analysis is used to analyze intramolecular interactions. NLO investigations indicate significant hyperpolarizability (β = 5.498 × 10⁻³⁰ esu), with values higher than those of urea. Frontier Molecular Orbital, MEP, and TD-DFT simulations in solvents yield a band gap of 3.80 eV, which has excellent electrical and optical properties. The NBO and Fukui analyses reveal stable donor-acceptor interactions and reactive regions. The SwissADME examination validated drug-likeness, and molecular docking revealed efficient interaction with tuberculosis target proteins, indicating anti-TB activity. These findings suggest that the compound not only possesses promising electronic characteristics but also demonstrates potential therapeutic applications. Overall, the molecule combines high biological activity with improved NLO responsiveness, making it a viable option for both therapeutic and photonic applications.

This work presents a theoretical and numerical investigation of the optical properties and slow-light behavior of CdS@ITO core–shell quantum dots (CSQDs) designed for operation in the 1310 nm and 1550 nm telecom bands. Using quasi-static electrodynamics, Maxwell–Garnett effective medium theory, and the Drude–Sommerfeld model, we demonstrate that the ITO shell supports low-loss infrared plasmonic resonances with extinction coefficients below (kappa < 0.06). Hybrid exciton–plasmon coupling between the CdS core and ITO shell produces strong local field enhancement ((|F|^{2}> 1000)) and pronounced normal dispersion, enabling slow-light behavior with group velocities as low as (v_{g} approx 0.05c). Geometric tuning of the core radius (3–5 nm) and shell thickness (6–8 nm) enables precise alignment of the plasmonic resonance with standard telecom wavelengths. Finite element simulations confirm intense field localization at the CdS/ITO interface and enhanced internal fields within the CdS core, supporting Kerr-type nonlinear effects relevant for optical modulation. Parametric mapping of extinction, refractive index, and group index further demonstrates robust spectral tunability and low-loss performance across the near-infrared region. These findings identify CdS@ITO CSQDs as promising, CMOS-compatible nanostructures for compact optical delay lines, all-optical modulators, and other integrated photonic components operating within the telecom band.

In this paper, a secure image hashing algorithm is proposed for content authentication. A novel algorithm termed Robust Feature-Guided Gridded Region Localization is designed first. This algorithm is utilized to locate highly discriminative regions with both robustness and uniform distribution. Then, the local and global structural features are extracted in parallel from these regions by employing spatial-topological kernel principal component analysis and rapid structure-preserving two-dimensional principal component analysis, and are subsequently combined to form the intermediate hash. To enhance security, a two-dimensional tent cubic coupling mapping with hyperchaos is further proposed to encrypt the hash. Experimental results demonstrate that the proposed algorithm possesses good robustness and discriminative properties when compared with recent baseline algorithms.

Using the AMPT model, we study charged hadron elliptic flow ((v_{2})) centrality dependence in Au+Au collisions at (sqrt{s_{NN}}=200~textrm{GeV}). We find distinct centrality-dependent roles for partonic ((sigma _{p})) and hadronic ((sigma _{H})) transport processes. In central collisions, (v_{2}) is dominantly amplified by larger (sigma _{p}) (reducing partonic viscosity) but insensitive to (sigma _{H}). In peripheral collisions, larger (sigma _{H}) (reducing hadronic viscosity) significantly enhances (v_{2}), flattening its centrality dependence and improving agreement with STAR data. Initial pressure gradients (enhanced by Lund parameter (a_{L})) also increase (v_{2}), while (b_{L}) affects spectra but not flow. This centrality-differential sensitivity to (sigma _{p}) and (sigma _{H}) provides a novel strategy for extracting phase-specific shear viscosities.

In the region of superheavy nuclei, where experimental data are scarce, theoretical calculations of separation energies and masses are vital for understanding their properties and potential stability. In this work, we calculate the proton and neutron separation energies for superheavy nuclei in the framework of a two-body model. To this aim, we first consider a nucleus as a two-body system, so using the Schrödinger equation in the presence of a nonrelativistic potential including the magnetic moments and Coulomb interactions, we determine the mass equation of the nuclei, analytically. Having the analytical solutions, we compute the ground-state mass of superheavy nuclei including Rf, Db, Sg, Bh, Hs, Mt, Ds, and Rg as well as the one- and two-nucleon separation energies. Our theoretical results are compared with the existing experimental data.

Background

In audio and speech signal processing, speech enhancement is thought of as a significant task. Speech improvement intends to improve the accessibility and excellence of an audio signal that has been weakened by ambient noise. The research on speech enrichment is the toughest process because of the degree of degradation of the speech signals. Diverse strategies for speech improvement are used based on the type of weakening and noise in the speech signal. As a result, the research in this area is still difficult, particularly when handling reverberation and extremely irregular noise. In this study, an enhanced speech enhancement framework is created using optimized deep learning techniques to improve both the quality and clarity of speech signals. At first, the required speech signal is collected from online resources. Further, the collected speech signal is directly passed to atrous convolution-based adaptive Trans-UNet (ACAT-UNet) with a novel loss function to attain the enhanced speech signal. Here, the loss function is incorporated with the deep learning model to enhance speech intelligibility. Furthermore, the speech enhancement performance of the ACAT-UNet is enhanced by fine-tuning the hyperparameters using the Updated Randomized Variable-based Aquila Optimizer (URVAO). The efficacy of the recommended speech improvement system is evaluated by conducting extensive simulations and experiments by contrasting it with other existing SE techniques. The numerical findings revealed that the suggested approach attained a root mean square error (RMSE) value of 0.226779.