Applied Physics A最新文献

This study investigates quiescent optical solitons in magneto-optical waveguides with nonlinear chromatic dispersion, using generalized temporal development and Kudryashov’s quintuple power law self-phase modulation. Two mathematical techniques, addenda to Kudryashov’s method (including two cases) and the enhanced direct algebraic method, are employed to recover these solitons.

ZnO nanoflakes were successfully synthesized via, sol-gel method using 2-methoxyethanol as a solvent and 2-mercaptoethanol as a surfactant. X-ray diffraction confirmed the hexagonal wurtzite structure of the ZnO nanoflakes, while FTIR spectroscopy verified the presence of ZnO vibrations. Scanning electron microscopy (SEM) revealed that the nanoflake-like morphology. The three electrode measurement demonstrates the battery behavior of the ZnO electrode which was observed from the CV studies. In this electrode exhibits maximum specific capacity of 420 C g^− 1, at specific currents of 2.5 A g⁻¹. AC- impedance studies reveals that low charge transfer resistance which makes the high power performance of the electrode material. Remarkably, the electrode demonstrated excellent cyclic stability, retaining its 92% capacity after 1600 charge-discharge cycles. These electrochemical findings suggest that ZnO nanoflakes are a promising electrode material for hybrid supercapacitor applications.

The creation of efficient storage systems that store and provide energy in an effective way to fulfil the energy requirements. This paper presents a simple hydrothermal technique for forming reduced graphene oxide sheets (rGO) based NdFeO₃ hybrid. The hybrid’s physical along with electrochemical characteristics have been investigated using different characterization techniques. The material exhibits potential for an electrode to be used in supercapacitors by virtue of its substantial surface area, distinctive structure, and combined action of metal ions. Significant storing capability is demonstrated by the NdFeO₃/rGO hybrid, which has increased capacitance of 1473 at 1 A/g with reduced solution resistance (R_s = 0.72 Ω) and strong cyclic stability after 5000^th cycle as well as mechanical stability of 50 h. The evaluations suggested that the hybrid has more ability for energy storing than the pure material.

This study investigates laser-induced decoration of soda-lime glass, emphasizing how laser parameters, particularly power and scanning speed, affect surface morphology and optical properties. An initial analytical model, inspired by existing literature, is developed to predict the dimensions of the laser-induced damaged zone (DZ) at the micro-scale level. A more refined numerical model is then introduced to reduce simplifying assumptions and access hard-to-measure physical values. Experimental validation enables the comparison of both models. Results show that the analytical model reliably predicts DZ width for moderate fluences (ϕ* < 3.1), while the numerical model yields better accuracy at higher fluences. For DZ depth, the analytical model is effective only up to ln(ϕ/Vₘ) < 5 (~ 100 μm); beyond that, it diverges. The numerical model offers more consistent results across the entire range, though with a slight underestimation. The study also explores the potential for reducing process parameters through the definition of a meta-parameter analogous to fluence, supporting broader industrial applications.

This study explores the interplay between the glass transition temperature (T_g) and nonlinear optical properties of a novel Polyurethane–Azobenzene–Carbon black (PAC) composite through Spatial Self-Phase Modulation (SSPM). By examining the temperature-dependent formation of SSPM diffraction rings, a strong correlation is established between the material’s thermo-mechanical transition and its optical nonlinearity. Below T_g, the composite exhibits suppressed SSPM activity due to restricted polymer chain mobility in the glassy state. Above T_g, enhanced segmental motion enables local refractive index modulation, leading to pronounced SSPM patterns. This transition is confirmed through both visual ring analysis and piecewise linear modeling, enabling accurate estimation of T_g. Complementary structural and optical characterizations, including XRD, Raman, and UV-Vis absorption spectroscopy, support the amorphous matrix and photoresponsive behavior of the PAC film. Notably, increased UV absorption at 20 °C indicates potential pre-transition softening, contributing to nonlinear effects even below bulk T_g. These results present SSPM as a powerful, non-contact optical tool for probing thermo-mechanical transitions in functional polymer composites and suggest the utility of PAC-based films in optically active sensor platforms.

The sol-gel dip coating approach synthesized cobalt-doped Bi₂O₄ nanostructures with Co doping 1-5wt.%. These nanostructures were ecologically beneficial. X-ray diffraction confirmed the synthesis of a monoclinic phase of Bi₂O₄ thin films. Bismuth oxide thin films with a 5 wt% Co has a higher lattice constant and larger crystallite size. The band gap of thin films decreased with an increase in Co contents, absorbing a large range of the visible spectrum of sunlight. The dielectric constant was increasing and the tangent loss was decreasing with an increase in Co contents, making nanostructures suitable for energy storage applications. The most significant discovery, which showed that cobalt-doped Bi₂O₄ thin films were feasible as low-cost spintronics devices, was the 11.5 emu/cm³ saturation magnetization value for 5wt.% Co doping. Cobalt-doped Bi₂O₄ exhibited elevated antibacterial activity against gram-positive (S. aureus) and gram-negative (E.coli, Klebsiella pneumonia and P. aeruginosa) pathogenic bacteria. Co-doped Bi₂O₄ nanostructures were an alternative to traditional photocatalysts due to their exceptional degradation performance in visible light. Both antibacterial and photo-catalytic activity have synergistic effects against pathogenic bacteria. These nanostructures offered enhanced photocatalytic performance, potential for environmental remediation, medical disinfection, and sustainable development.

This study presents the fabrication and optimization of fluorine-free silica-based thin films with tunable wettability for self-cleaning applications. Silica nanoparticles were synthesized via a sol–gel spin-coating process using tetraethyl orthosilicate (TEOS) as the precursor, followed by thermal annealing in an air ambient and surface modification using hexamethyldisilazane (HMDS). The influence of TEOS concentration and annealing temperature on nanoparticle size, surface morphology, and wettability was systematically investigated. Structural study by X-ray diffraction technique for all the samples illustrated an amorphous structure of silica thin films with a broad peak around 24^ο without shifting the peak position. Field emission scanning electron microscopy (FESEM) revealed that increased TEOS concentration led to larger particle sizes and enhanced surface roughness. Fourier-transform infrared spectroscopy (FTIR) confirmed successful salinization, and UV-vis spectroscopy showed moderate optical transparency (45%) in the visible/UV-Vis range. Contact angle measurements demonstrated a transition from hydrophilic to superhydrophobic behaviour (up to ~ 139°), governed by surface roughness and chemical modification. The results indicate that the size of the synthesized nanoparticles is closely linked to the TEOS precursor concentration, while their hydrophobic properties are influenced by the HMDS functionalizing agent. This research work signifies a scalable, cost-effective, and environmentally friendly approach for the fabrication of silica film without using fluorinated compounds.

The goal of this investigation is to evaluate the validity of the phenomenological model (PM) for the magnetocaloric effect (MCE) in Ni₂Mn_0.55Cu_0.35Fe_0.10Ga during the first order phase transition (FOPT) at 5 T. Furthermore, the MCE of Ni₂Mn_0.55Cu_0.35Fe_0.10Ga during the second order phase transition (SOPT) is studied. Interestingly, the agreement between the simulated magnetic entropy change (3.5 J/kg.K) and the reported one (3.2 J/kg.K) for FOPT is quite precise across the whole temperature range. Furthermore, Ni₂Mn_0.55Cu_0.35Fe_0.10Ga ‘s relative cooling power has been calculated to be 207 and 73 J/kg for SOPT and FOPT, respectively. Moreover, the simulated heat capacity change via the FOPT reaches a maximum value of 90.8 J/kg.K. These findings suggest that PM is a reliable model for studying MCE in the FOPT and SOPT since it reduces the time and effort necessary to compute and quantify it. Consequently, we believe the PM can be utilized for predicting the MCE parameters in any magnetic transition. It is indicated that Ni₂Mn_0.55Cu_0.35Fe_0.10Ga can be employed as an essential refrigerant magnet at ambient temperature and at higher and lower temperatures.

Crystallization of the prepared transparent 2MgO-2Al₂O₃-3.33B₂O₃ glass system into a well glass-ceramic with optimized crystalline phases that simultaneously improve dielectric properties and lower thermal expansion (CTE) for enhanced functional performance. Despite its chemical equivalence to cordierite stoichiometry (2MgO-2Al₂O₃-5SiO₂), the investigated composition completely substitutes SiO₂ with B₂O₃. The nucleation efficiency of individual (TiO₂, ZrO₂) and combined TiO₂-ZrO₂ additives was rigorously evaluated. The glass-ceramics developed in this work exhibit tailored physicochemical properties (density, hardness, CTE, dielectric properties). Differential thermal analysis (DTA) identified a high crystallization (773–794 °C) for TiO₂-ZrO₂-doped formulations. Phase evolution studies confirmed the crystallization of kotoite (Mg₃B₂O₆), sinhalite (MgAlBO₄), aluminum borate (Al₄B₂O₉), baddeleyite (ZrO₂), and aluminum titanate (Al₂Ti₇O₁₅) at 800–900 °C. The SEM analysis of 900 °C-treated samples revealed a microstructure of submicron rod-like crystallites dispersed in a residual glass phase. Thermo-mechanical characterization yielded CTEs of 12.42–27.55 × 10⁻⁷ °C⁻¹ (25–300 °C) and 22.45–39.19 × 10⁻⁷ °C⁻¹ (25–400 °C). The glass-ceramics (density: 2.54–2.65 g/cm³; hardness: 5.42–5.85 GPa) exhibited superior dielectric properties (high dielectric constant, low dielectric loss) relative to parent glasses (2.61–2.73 g/cm³; 5.11–5.89 GPa), attributable to TiO₂/ZrO₂-derived crystalline phases (Al₂TiO₅, ZrO₂). These attributes combined with low CTE and density suggest viability for microwave substrates or electronic applications.

Synthesis and detailed characterization of Zn_0.98−xSi_0.02Ti_xO nanocomposites, where titanium content varies from 0.0 to 0.20, were presented. It is employed a straightforward solid-state reaction is employed to prepare the nanocomposites. X-ray diffraction analysis confirmed that the hexagonal wurtzite structure remains intact while experiencing systematic lattice expansion. The a-parameter increased from 3.25 Å to 3.28 Å, and the c-parameter grew from 5.21 Å to 5.24 Å with Ti-incorporation. Crystallite dimensions decreased from 28.3 nm in pure samples to 26.01 nm in heavily doped variants, while dislocation density rose from 1.05 × 10¹⁴ to 11.9 × 10¹⁴ lines/m² by using the Williamson-Hall formula. Scanning electron microscopy showed grain size changes from 300 to 400 nm to a broader 200–400 nm distribution. Temperature-dependent electrical measurements revealed activation energies between 0.089 and 0.129 eV. Optical properties demonstrated band gap widening from 3.21 eV to 3.26 eV, consistent with the Burstein-Moss phenomenon. These findings highlight the potential of controlled titanium doping for developing advanced optoelectronic devices.