Brazilian Journal of Physics最新文献

The search for advanced energy storage devices has extensive research into batteries beyond the conventional lithium-ion battery. As we know, now researchers are actively exploring alternative energy storage technologies, focusing on abundant elements such as calcium (Ca), magnesium (Mg), sodium (Na), and zinc (Zn). These alternatives promise to reduce the limitations of lithium resources, offering potentially lower costs, higher resource availability, and diverse chemistries for various applications. This short review provides an overview of recent advancements in next-generation battery storage systems mainly on the alternate to Li-ion battery, focusing on innovations in battery chemistry, energy density, safety, and integration with renewable energy sources. The review explores the significance of enhancing battery technology for various uses like electric vehicles and large-scale energy storage systems. It emphasizes notable advancements and hurdles encountered in this domain. The various types of batteries and their anode, cathode, and electrolyte materials were discussed briefly, in the present review. The present work will be helpful for the budding researchers who work in the field of energy storage systems, to acquire a knowledge on the recent trends and future technology of battery storage systems towards the alternate solution for Li-ion battery.

The interaction between aquatic organisms and plants is crucial to maintaining the ecological balance of the marine environment. This study aims to investigate the effects of providing refuge on phytoplankton and the delay in releasing hazardous substances by phytoplankton. To accomplish this, a nutrient-phytoplankton-zooplankton system was developed and analyzed to examine its equilibria and the conditions under which they exist. The model’s stability was also analyzed, both in the absence and presence of time delays. The inclusion of a time delay caused a Hopf bifurcation at the interior equilibrium of the model, resulting in a transition from stability to instability. The study found that as the time delay value increases, the system’s stable dynamics transition into an unstable state. However, because phytoplankton refuge is part of the system, the dynamics temporarily become stable, even though phytoplankton release the toxins over a long time. However, this stable behavior is disrupted when the time required for the toxin liberation process by phytoplankton is further extended.

This study examines the head-on collision of ion-acoustic solitons in a one-dimensional, hot, collisionless electron-positron-ion (e-p-i) plasma, incorporating mobile ions, (kappa )-distributed trapped electrons, and Maxwellian positrons. Using the modified Poincare-Lighthill-Kuo (PLK) method, we derive modified Korteweg-de Vries (mKdV) equations and analyze phase shifts in soliton trajectories post-interaction. Results reveal that only rarefactive electrostatic nonlinear waves can propagate within the range of parameters relevant to experiments, showing symmetrical soliton behavior during head-on collisions, with identical amplitude and width. Additionally, soliton amplitude is found to decrease as the electron spectral index ((kappa _e)) and positron-to-electron temperature ratio ((beta _e)) increase, with a sharp decline observed within the range (0<kappa _e<5). Phase shift analysis shows that smaller (kappa _e) values result in a steady increase in phase shifts, which becomes asymptotic as (kappa _e) grows, while phase shifts decrease with rising (sigma _i) (temperature ratio of ions to electrons). These results have practical applications in astrophysical and laboratory plasma environments where soliton interactions play a crucial role. Understanding head-on soliton collisions helps predict plasma behavior in environments such as the interstellar medium, fusion devices, and space plasmas, where wave stability, energy transport, and plasma heating are influenced by nonlinear interactions in systems with trapped particles and nonthermal distributions.

We propose a stochastic dynamics to be associated to a deterministic motion defined by a set of first order differential equation. The transitions that defined the stochastic dynamics are unidirectional, and the rates are equal to the absolute value of the velocity vector field associate to the deterministic motion. From the stochastic dynamics, we determine the entropy production and the entropy flux. This last quantity is found to be the negative of the divergence of the velocity vector field. In the case of a Hamiltonian dynamics, it vanishes identically.

The overtaking collision of dust acoustic waves (DAWs) featuring electrons distributed according to a hybrid Cairns-Tsallis model and Boltzmann-distributed ions is investigated in this paper. The Korteweg de Vries (KdV) equation, which permits rarefactive DAWs, is the result of nonlinear research of the plasma system utilizing the reductive perturbation approach. Using Hirota’s bilinear method, the overtaking interaction between two and three-soliton solutions is examined. Physical factors that affect the overtaking collisions and change the dynamics of the solitons include electron density, dust radius ratio, and nonextensive parameters. Interestingly, the solitons amplitude and width grow when the electron density and dust radius ratio rise or the nonextensivity falls. In addition, the system’s properties have an impact on the phase alterations of the solitons. The information offered here may be useful for the investigation of DAWs in dusty space plasmas, including cometary environments, the F and G rings of Saturn, and laboratory plasmas with nonthermal nonextensive electrons.

Mg_0.5Cu_0.8Er_xFe_2−xO₄ (through x = 0.000, 0.005, 0.010, 0.015, 0.020, 0.025 and 0.030) A series of rare earth (Er³⁺)-doped magnesium-copper nanoparticles with the general chemical compositions of Mg0.5Cu0.8ErxFe2−xO4 (through x = 0.000, 0.005, 0.010, 0.015, 0.020, 0.025 and 0.030) was fabricated by citrate sol–gel auto combustion technique. The fabricated materials are investigated through XRD, FE-SEM, EDS, TEM, FTIR, UV–Vis, DC resistivity, and TEP properties. The crystallite size of the samples was determined to be 33–40 nm with increased Er³⁺ concentration, and the XRD investigations validated the spinel cubic structure of the samples with the space group Fd-3 m. The lattice constant was found to decrease from 8.403 to 8.356 Å. The morphology of FE-SEM micrographs was found to be spherical shape. TEM micrographs show that average particle size decreases from 64 to 48 nm. The nanoparticles’ FTIR examination revealed that their ʋ₁ and ʋ₂ absorption bands were between 401–412 cm⁻¹ and 547–562 cm⁻¹. The optical band gap was measured using UV–vis spectroscopy and found between 1.81 and 2.38 eV. In Mg–Cu nano-ferrites with Er-doping, there was no noticeable increase in the elasticity moduli. With increasing Er-doping and composition, it has been found that the thermal energy needed to change the p-type Mg–Cu nano-ferrites’ behavior from semiconducting to n-type semiconducting behavior increases. Er-doped Mg–Cu ferrites demonstrate a metal–semiconductor behavior according to DC resistivity exploration.

The structural and luminescence properties of akermanite type compound Sr₂MgSi₂O₇:Sm³⁺ have been investigated. The crystal structure of Sr₂MgSi₂O₇ has been obtained from the X-ray diffraction data. Sr₂MgSi₂O₇ possesses tetragonal symmetry with space group P (overline{4 }) 2₁ m (No. 113). Judd Ofelt (J-O) analysis of akermanite structured Sm³⁺-doped Sr₂MgSi₂O₇ phosphor synthesized by combustion synthesis followed by a solid-state reaction process is presented. SEM confirms the morphology. The photoluminescence emission (PL) spectra indicate that the phosphor gives orange red emission at 601 nm attributed to transitions ⁴G_5/2 (to) ⁶H_5/2. Optimum concentration is found to be 7.0 mol.%. The CIE chromaticity coordinates are (0.57, 0.43). The branching ratio for the transition, ⁴G_5/2 (to) ⁶H_7/2, is found to be around 53%, suggesting it as a potential laser material in addition to its use for fabrication of white LED phosphors.

This investigation examines fractional higher-order evolution and fundamental wave equations, namely the third- and fifth-order fractional Korteweg-de Vries (KdV)-type equations, which regulate diverse nonlinear physical processes, especially those occurring in fluids and plasmas. For this purpose, the Aboodh/Laplace residual power series method (ARPSM) and the Aboodh/Laplace transform iterative method (ATIM) are carried out to derive high-accurate approximations. These methods are applied in conjunction with the Caputo operator, which effectively handles the fractional derivatives. The results illustrate the efficacy of both ARPSM and ATIM in analyzing third- and fifth-order time fractional KdV-type equations, providing valuable insights and potential applications in fractional calculus and its applications to complicated physical and engineering issues. The derived approximations are investigated graphically and numerically to understand the effect of the fractional parameter on the properties of the nonlinear phenomena characterized by this family. Furthermore, the precision and efficacy of the suggested techniques are verified by comparing the derived approximations to the exact solutions for the integer-order cases. The findings of this investigation have the potential to benefit a wide range of researchers who are interested in optical physics, fluid physics, and plasma physics. They can be employed to analyze and comprehend the results of their laboratory and space observations.

The quaternary material consisting of copper, zinc, tin and sulfur has long attracted the attention of the scientific world in the development of thin layers for photovoltaic applications. In this work, we proposed to make the junction between the absorbent layer consisting of copper-zinc-tin-sulfur Cu₂ZnSnS₄ (CZTS) and different buffer layers such as zinc sulfide ZnS, tin disulfide SnS₂, and cadmium sulfide CdS for comparison purposes, in using the simple and low-cost technique of spray pyrolysis at 380 °C for all stages. All the films obtained were characterized by X-ray diffraction (XRD), and UV–visible spectroscopy and the morphology and topography of the layers were assessed under the scanning electron microscope (SEM) and EDXA. Characterization results showed the formation of CZTS thin films whose kesterite structure was improved by annealing at 450 °C under sulfur atmosphere. The grain size also improved from 6.7 to 7.9 nm after annealing. Subsequently, a simulation study by SCAPS-1D is made to assess the efficiency of the photovoltaic cell thus produced. It exhibited the highest power conversion efficiency (PCE) for the cell using SnS₂ as a buffer layer, i.e., 20.25%, compared to 16.14% for the cell using CdS. This confirmed the possibility of favoring SnS₂ in the design of CZTS-based solar cells, suggested in the literature, as a replacement for CdS, and this by the simple technique of spray pyrolysis.