The European Physical Journal Plus最新文献

We investigate the mass spectra of heavy tetraquark systems modeled as diquark–antidiquark bound states within a conformable fractional extension of the spinless Salpeter equation, hereafter referred to as the Conformable Salpeter Framework. A fractional-order wave equation is derived from first principles using the conformable fractional derivative with order parameter (0<alpha le 1) and is solved analytically with the fractional Hellmann potential. The classical ((alpha =1)) limit reproduces the integer-order results reported in previous studies, confirming consistency of the framework. Binding energies and masses are computed for hidden-charm ((cbar{c})) and hidden-bottom ((bbar{b})) tetraquarks with quantum numbers (J^{PC}=0^{++}), (1^{+-}), (1^{++}), (2^{++}). The predicted masses are compared with experimentally observed exotic states including X(3872), Y(3940), (Z_{cs}(3985)), X(4140), (Z_b(10610)), and (Z_b(10650)) reported by the Belle, CDF, and BESIII collaborations, and with results from other theoretical models. The present study is further extended to fully heavy (ccbar{c}bar{c}) and (bbbar{b}bar{b}) tetraquarks. Variations of (alpha ) between 0.2 and 0.6 provide a continuous tuning of mass predictions, with deviations from experiment typically below 0.5%, demonstrating the flexibility and reliability of the conformable fractional approach.

Multifunctional nanocomposites were prepared by incorporating varying loadings of silver nanoparticles (Ag NPs) into a sodium carboxymethyl cellulose (CMC) matrix using the solution casting technique. The films produced were systematically examined for their structural, morphological, optical, dielectric, and antibacterial characteristics. XRD confirmed the formation of crystalline Ag phases within the predominantly amorphous CMC matrix. FTIR shows changes indicating a shift in the local chemical environment of CMC functional groups, suggesting interactions between the oxygen-containing groups of CMC and the Ag nanoparticles, as well as a disruption of the native hydrogen bonding network of the polymer matrix. TEM examination revealed statistically distributed quasi-spherical Ag nanoparticles with an average diameter of around 38 nm, whereas FESEM/EDX indicated the presence of Ag particles with different sizes, including clustered structures. UV–Vis diffuse reflectance analysis indicated a notable reduction in the optical band gap as the concentration of silver NPs increased. The refractive index dispersion of the CMC/Ag nanocomposites strongly depended on Ag loading. The highest refractive index values (1.26–1.60) were obtained for 1 wt.% Ag, followed by 3 wt.% and 6 wt.%, whereas the lowest values (1.06–1.14) were observed for 9 wt.% Ag. Dielectric measurements revealed an increase in conductivity with increasing Ag concentration, and the charge transport mechanism followed the Correlated Barrier Hopping (CBH) model. Furthermore, the CMC/Ag nanocomposites exhibited enhanced antibacterial activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria, with inhibitory efficacy increasing with increasing Ag NP concentration. These results illustrate the synergistic effect of Ag nanoparticles and the CMC matrix on the physicochemical characteristics of the nanocomposites, making them promising candidates for optoelectronic, dielectric, and biological applications.

This paper introduces a modified three-dimensional Sprott-type system without equilibrium points by combining a smooth hyperbolic-tangent feedback term with a quartic nonlinearity. The proposed model exhibits bounded multispiral chaotic dynamics, quasi-conservative behavior, and rich hidden multistability involving coexisting quasiperiodic and chaotic motions. Its nonlinear properties are investigated through equilibrium analysis, divergence, Lyapunov exponents, bifurcation diagrams, phase portraits, and Poincaré-based representations. The Lyapunov analysis is verified using the variational-equation method with periodic QR orthonormalization. As an application, six chaotic sequences generated by the system are incorporated into a two-round confusion–diffusion–permutation image-encryption framework with an image-dependent SHA-256 key update. The encryption performance is assessed through key sensitivity, histogram and correlation analyses, NIST statistical tests, differential measures, entropy, robustness, and computational cost. In addition, an analog circuit realization is examined through MultiSim simulations, supporting the practical feasibility of the proposed chaotic system.

Phosphogypsum (PG), a by-product of phosphate fertilizer production, has been widely considered for reuse in construction materials in line with the principles of the circular economy. However, PG and associated secondary compounds such as metasilicate phosphate often contain naturally occurring radionuclides, including ²²⁶Ra, ²³⁸U and ²³²Th, which may pose radiological hazards. This study assesses terrestrial and marine radiological exposure scenarios associated with phosphate industry residues used in road construction and stored at a former coastal industrial deposit in Crotone (Calabria, Italy). Sixteen road-pavement composite cores and 28 deposit-site samples were investigated by high-resolution gamma-ray spectrometry. Maximum activity concentrations in the road-pavement samples reached 1235 Bq kg⁻¹ for ²³⁸U, 1212 Bq kg⁻¹ for ²²⁶Ra and 317 Bq kg⁻¹ for ⁴⁰K. The ERICA Tool was applied using a screening dose rate of 10 µGy h⁻¹. For several terrestrial and marine reference organisms, risk quotients exceeded unity, triggering Tier 2 and Tier 3 assessments. These screening exceedances indicate that the scenarios could not be screened out as being of low radiological concern. Tier 2 identified lichens and bryophytes as the most exposed terrestrial reference organism and phytoplankton as an important marine reference organism. Tier 3 sensitivity analysis showed that uncertainty in ²²⁶Ra transfer parameters strongly controlled variability in predicted dose rates. The marine calculations represent a conservative nearshore sediment deposition scenario because radionuclide concentrations were not measured directly in seawater, marine sediment or biota. The results support improved control, monitoring and site-specific characterization of exposed NORM-containing residues in coastal environments.

Graphical abstract

This paper presented YOLO-MUBL, an enhanced YOLOv11n-based approach designed specifically for PCB defect identification tasks. The original C3k2 building block was substituted with a novel C3k2-MambaOut-UniRepLK composite module, which combined gated convolutional feature interaction with large-kernel spatial modeling to strengthen the feature representation of minute defects. Furthermore, we embedded a Bi-Level Routing Attention (BRA) module into the backbone framework, which served to preserve high-resolution spatial details and support dynamic cross-scale feature communication. We also focused on improving edge deployment efficiency. To this end, we devised a lightweight shared convolution detection head (LSCD-Head). This design achieved two major reductions: It shrank the model’s parameter budget and also lessened the computational burden during inference. Experimental findings demonstrated that YOLO-MUBL attained 94.1% mAP@ 0.5 and 50.7% mAP@ 0.5:0.95 on the PCB defect dataset, representing improvements of 2.0% and 1.3%, respectively, over the baseline model. The parameter count decreased from 2.583 to 2.278 M, and GFLOPs dropped from 6.3 to 6.2. We proceeded with deployment on the Fibocom SC171V2 edge platform. Performance evaluation showed that each frame required only 30.8 ms for inference, while the system consistently operated at 25 frames per second. These results affirmed that our approach is well suited for industrial use scenarios.

The present study comprehensively investigates the γ-ray shielding performance of recycled marble reinforced with different Sb₂O₃ contents. Marble powder was mixed with 20, 30, and 50 wt% Sb₂O₃, thoroughly homogenized, and compacted into tablets of varying thicknesses. The elemental composition of the prepared composites was verified by X-ray fluorescence (XRF), while their attenuation characteristics were experimentally evaluated using narrow-beam transmission geometry with ¹³⁷Cs (662 keV) and ⁶⁰Co (1173 and 1332 keV) γ-ray sources. The transmitted radiation was measured using a NaI(Tl) scintillation detector coupled to a multichannel analyzer, and the linear and mass attenuation coefficients were determined from the Beer–Lambert law. The experimental results were compared with theoretical predictions obtained from the NIST XCOM and Phy-X/PSD using the XRF-derived compositions. The results demonstrated that incorporating Sb₂O₃ significantly enhanced the γ-ray shielding performance compared with undoped marble. A nonlinear dependence of the shielding performance on Sb₂O₃ content was observed, where the addition of 20 wt% Sb₂O₃ markedly improved the mass attenuation coefficient, whereas further increasing the Sb₂O₃ content to 50 wt% produced only marginal additional improvement. This saturation behavior is attributed to the predominance of Compton scattering in the investigated energy range. At 662 keV, the SB50 composite exhibited a mass attenuation coefficient approximately 87% that of pure lead and approximately 28% higher than that of conventional concrete. These findings demonstrate the potential of marble/ Sb₂O₃ composites as sustainable, lead-free, and cost-effective materials for γ-ray shielding applications.

This study proposes an all-dielectric composite nanograting structure comprising a TiO₂ subwavelength grating and a SiO₂/TiO₂ multilayer dielectric film, designed to achieve high-reflectance modulation and refractive index (RI) sensing in the visible spectrum. A theoretical model was established based on the effective medium theory (EMT) and the transfer matrix method (TMM). Furthermore, the finite-difference time-domain (FDTD) method was employed to systematically analyze the effects of the number of multilayer periods, duty cycle, and grating height on the reflection spectra. The results indicate that the bottom multilayer film significantly enhances the optical feedback. Specifically, when the number of periods reaches N = 5, the structure achieves a maximum reflectance of over 99%. Variations in the duty cycle and grating height can effectively tune the resonance wavelength while maintaining a stable Fano resonance lineshape. The proposed structure achieves a RI sensitivity of 465.97 nm/RIU within the ambient RI range of n_c = 1.33–1.37, alongside a quality factor of 153.3, demonstrating a highly linear response and excellent application potential.

We investigate exact three-dimensional vortex solitons in nonlinear media with transverse modulation potentials and inhomogeneous cubic–quintic nonlinearities. By separating variables in spherical coordinates, we derive analytical solutions to the governing nonlinear wave equation, expressed via Jacobi elliptic functions and parameterized by quantum numbers (n), (ell), and (m). A variety of structures are revealed, including multilayer ellipsoids, toroidal rings, hollow vortices, and symmetric multipolar patterns. Numerical simulations show that solitons with (n = 1) and (ell = 0, 1) are stable, while those with (ell ge 2) or (n ge 2) are unstable. Our results may useful for the generation and control of three-dimensional vortex solitons in nonlinear optics and Bose–Einstein condensates.

Study delves into the multifaceted properties of Tb³⁺-doped TiO₂ nanomaterials synthesized via hydrothermal process at 160 °C. The photoluminescence studies unveil a remarkable enhancement in luminescent properties attributed to efficient energy transfer mechanisms from the host matrix to terbium ions. The role of concentration in modulating non-radiative energy transfer processes, facilitating direct excitation of terbium ions for enhanced performance, has been highlighted. Emission spectral outcomes at the excitation of 350 nm showcase an exceptional color purity of 96.7% is corroborated by Commission Internationale de l’Eclairage (CIE) chart analysis, which demonstrates adherence to National Television System Committee (NTSC) standards with coordinates (0.31, 0.57). Such outstanding color purity positions the studied nanophosphors as promising contenders for a wide array of applications, spanning lighting, displays, and green laser technology. In essence, the comprehensive optical characterizations presented in this study underscore the remarkable suitability of Tb³⁺-doped TiO₂ nanophosphors for diverse technological applications, heralding a new era of innovation in materials science, optoelectronics, and photonics.