Revista Mexicana de Física

World personal income distribution evolution measured by purchasing power parity exchange rates

Jesus Domingo Alfin J.D.A. Islas-García — 2025-11-01

The evolution of global income distribution from 1988 to 2018 is analyzed using purchasing power parity exchange rates and well-established statistical distributions. This research proposes the use of two separate distributions to more accurately represent the overall data, rather than relying on a single distribution. The global income distribution was fitted to log-normal and gamma functions, which are standard tools in econophysics. Despite limitations in data completeness during the early years, the available information covered the vast majority of the world’s population. Probability density function (PDF) curves enabled the identification of key peaks in the distribution, while complementary cumulative distribution function (CCDF) curves highlighted general trends in inequality. Initially, the global income distribution exhibited a bimodal pattern; however, the growth of middle classes in highly populated countries such as China and India has driven the transition to a unimodal distribution in recent years. While single-function fits with gamma or log-normal distributions provided reasonable accuracy, the bimodal approach constructed as a sum of log-normal distributions yielded near-perfect fits.

Physical properties of two-dimensional and quasi-two-dimensional systems

J. D. Hernández Velázquez — 2025-11-01

A short review of some recent works on the similarities and differences in the physics of two-dimensional (2D) and quasi-two-dimensional (Q2D) systems by mesoscale models is presented. Three different case studies are reported: (a) two immiscible liquids, (b) a low density, classic Coulomb gas, and (c) dense polymer melts; all of which are under highly confined, Q2D geometry. Among our leading results are the following: the line tension of Q2D systems displays the same scaling exponent as the strictly 2D case. The Q2D Coulomb gas undergoes a topological phase transition closely related to the 2D Kosterlitz-Thouless transition, although important differences arise. Lastly, a scaling law for polymer melts in Q2D is proposed and tested, showing that the structure of the melt goes through fractal transitions with increasing concentration. In addition to the novelty of the results reported here and to their agreement with established theories and experimental data, this work highlights the usefulness of Q2D models to test known and underexplored physical phenomena expected for strictly 2D systems, which are never truly achieved in nature.

Synthesis and characterization of Cu2O thin films obtained from a CO2-N2 plasma mixture

Marcos C. Gonzalez — 2025-11-01

In this study, a CO₂-N₂ plasma mixture was used to synthesize Cu₂O thin-films oxides metallics in a pulsed sputtering system. The plasma was generated using a percentage of 80% CO₂-20% N₂ between two copper (Cu) electrodes. The Cu₂O obtained were characterized by Raman spectroscopy, with the intention of detecting the bonding structure of the deposited thin films, while scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to study the surface morphology of the thin film. Dispersion Analysis (EDS) was conducted to determine the stoichiometric equilibrium present in the sample. The plasma characterization was performed during the deposition process using optical emission spectroscopy (OES), and the influence of the deposition process parameters on the chemical fragmentation of species present in the plasma was determined. The Raman results confirm the presence of Cu₂O films, and SEM analysis showed an irregular surface on the Cu substrate, forming a non-homogeneous surface. The morphology observed through AFM indicated that the thin films grew as islands, corroborating the generation of amorphous structures grown on the Cu surface. EDS analysis confirmed the presence of only copper and oxygen in the sample, whereas OES spectra confirmed the dissociation of CO₂ within the plasma, allowing for the presence of oxides within it.

Comprehensive review of chemical cleaning in polyvinylidene fluoride/graphene oxide-based membrane for oilfield-produced water treatment

Febriani Febriani — 2025-11-01

The high demand for oil results in an oilfield-produced water (OPW) production increment. The management of OPW presents a significant environmental and industrial challenge, attributed to its intricate composition, which encompasses hydrocarbons, suspended solids, and salts. Polyvinylidene fluoride (PVDF)/graphene oxide (GO)-based membranes, represent effective options for oil-water separation, attributed to their enhanced mechanical strength, hydrophilicity, and resistance to fouling. Maintaining the durability and performance of these membranes requires effective chemical cleaning strategies to mitigate fouling issues. This review discusses the fouling mechanism that takes place in OPW treatment, reviews chemical cleaning of the membranes utilized in OPW treatment, and compares the chemical cleanability of PVDF/GO-based membranes. The findings indicate that the chemical cleaning process of PVDF/GO-based membrane can be aligned with that of the PVDF membrane. The incorporation of GO in PVDF-based membranes can mitigate membrane fouling. The use of chemicals can be decreased as fouling decreases. This mitigates potential harm to the membrane during the chemical cleaning procedure, particularly when employing chemicals that are susceptible to resulting in damage. When the fouling is reduced, the chemicals used can be reduced, hence reducing the potential damage to the membrane during the chemical cleaning process, especially when using chemicals prone to causing damage. This study analyses recent developments and proposes future directions to optimize the cleaning process, enhancing the sustainability and operational efficiency of PVDF/GO-based membranes in OPW treatment applications.

3D Printing for microfabrication and mechanical stress characterization in flexible electronics

Angel Gonzalez — 2025-11-01

In this work, the application of 3D printing for microfabrication and mechanical stress characterization in flexible electronics is presented. The 3D printing method used is fused deposition modeling with polylactic acid (PLA) filament as an eco-friendly alternative. For mechanical stress characterization, a 3D device is designed to be adapted to the requirements of flexible samples showing accuracy, versatility and easy implementation in any probe-station. For microfabrication, a PLA 3D shadow mask is used to transfer silver patterns to flexible substrates such as Polyethylene Terephthalate (PET) and photographic paper. A systematic study to evaluate the mechanical stress in the silver patterns is conducted using the 3D printed devices previously designed. The silver film is evaporated using a thermal evaporating coater. Finally, to demonstrate a flexible Printed Circuit Board (PCB) application, a silver path evaporated on PET substrate is used as a transmission line for a sine electrical signal. The flexible PCB exhibits a reliable electrical operation even when the substrate is bent.

Effect of the thermomechanical properties of hybrid materials on the performance enhancement of nano terahertz antennas

Mohamed BELHAMIANI — 2025-11-01

This study investigates the impact of the thermomechanical properties of hybrid materials, such as polymer substrates and gold or graphene radiating elements, on the performance enhancement of nano terahertz antennas, with a specific focus on the combination of graphene and polyimide. We analyze how the Young’s modulus of materials like graphene, Gold, PTFE, polycarbonate and polyimide varies with temperature. Results show that graphene maintains high rigidity with minimal decrease in Young’s modulus even at elevated temperatures, whereas gold exhibits a more pronounced reduction. Among polymer substrates, polyimide exhibits increasing rigidity with temperature, making it highly suitable for high-temperature applications. Combining graphene with polyimide to concept terahertz antenna with dimension of 64.97*90.84*1 provides an optimal balance of low reflection coefficients S11 of -20.59dB and high gain of 6.01 dBi, demonstrating excellent performance and stability in the THz frequency range. Hybridizing polymer substrates with graphene or gold antennas merges the mechanical benefits of polymers with the exceptional electrical and optical properties of graphene and gold. This approach facilitates the creation of lighter, more flexible, and durable devices while enhancing performance in terms of sensitivity and resistance across a range of innovative technological applications.

Carbon nanomaterial from watermelon skin waste as liquid supplement for Lettuce sativa L. in hydroponics system

Nisrina Hasna Mustofa — 2025-11-01

Carbon nanomaterials have been used in various fields such as agriculture because they have properties that allow them to influence plant growth. This research aims to determine the effect of carbon nanomaterial made from watermelon skin waste as a plant supplement towards the growth of lettuce (Lettuce sativa L.) plants in a hydroponic setting. This research began by making carbon nanomaterial powder, which had been dried using an oven. Then the carbon nanomaterial liquid is heated again using a microwave to obtain a carbon nanomaterial sample in powder form. Carbon nanomaterial samples were characterized using UV-Vis, PSA, and XRD. The carbon nanomaterial solution was compared with a media that only used water. Data collection was carried out by measuring water level, leaf width, plant height, number of leaves, and wet and gross weights of the lettuce plants. The results showed that the carbon nanomaterials can influence the growth and development of lettuce plants. However, carbon nanomaterials only focus on helping plants absorb water and controlling and developing plants’ growth so that they experience more stable growth.

Bound and scattering state energies of Hulthén-Hellmann potential with external field and topological defects

Uduakobong Sunday Okorie — 2025-11-01

Topological defect and external fields influence on potential models has been significantly proven to shape the behaviour and interactions of different constituent quantum systems. Due on this fact, we employ the Nikiforov-Uvarov functional analysis method to solve the Schrödinger equation with Hulthén-Hellmann Potential, embedded with Aharonov-Bohm flux field and point-like global monopole defect. Analytical expression of the energies with topological defect and AB flus field was obtained. In addition, the scattering phase shift expression of the combined potential was obtained under the influence of the global monopole and external field. Numerical and graphical variations have been presented for various quantum states, flux field and topological defect values. It is observed that, energy eigenvalues and scattering phase shift of the combined potential are significantly affected by the topological defect parameters, Aharonov-Bohm flux field, screening parameter and quantum state values considered, in the curved space-time. Conventional results of this study in Minkowski space-time are realized as the topological defect parameter approaches unity, in the absence of the AB flux field and these results agree with available results in literature. The results in this study also point relatively to some physical phenomena in chemical and molecular physics.

Assessing the viability of Caesium-based double perovskite for technological applications

Houda Mansour — 2025-11-01

This research aims to provide a comprehensive understanding of the structural, elastic, electronic, and optical properties of the Cs2PbBeBr6 halide double perovskite (HDP). In this study, all self-consistent field (SCF) calculations were performed using density functional theory (DFT) within the full-potential linear augmented plane-wave (FP-LAPW) method, as implemented in the Wien2k code. The Perdew-BurkeErnzerhof (PBE) generalized gradient approximation (GGA) and the Tran-Blaha modified Becke−Johnson (TB-mBJ) methods were employed to accurately describe the exchange-correlation interactions. Our findings indicate that Cs2PbBeBr6 is stable in a cubic structure (Fm-3m), supported by phase stability analysis, enthalpy of formation, tolerance factor, and elastic constants. The compound exhibits ductile behavior, as assessed by Poisson’s and Pugh’s ratios. The electronic band structure reveals an indirect band gap of 2.243 eV and 3.248 eV, calculated using the GGA and TB-mBJ methods, respectively. Optical spectra calculations were performed in the energy range of 0 to 13 eV for each of the dielectric functions, extinction coefficient, electron energy loss, refractive index, optical conductivity, reflectivity, and absorption coefficient. The optical properties of Cs2PbBeBr6 in the visible range are particularly significant, offering strong potential for applications such as solar energy harvesting. These characteristics make the compound a promising candidate for optoelectronic devices.

A comprehensive algorithm using a fixed toroidal magnetic field for plasma equilibrium with flow

Amina DJELLOULI — 2025-11-01

This study presents a finite element method (FEM) solver developed to compute the steady equilibrium of an axisymmetric plasma with toroidal flow. The main objective of the algorithm is to determine the free parameters of the toroidal current source using two key constraints: the measured toroidal magnetic field (TMF) at the magnetic axis and the global error defined by Hilbert. To ensure the accuracy of the performed code, the validation was performed using typical parameters of the JT-60SA (Japan Torus-60 Super Advanced) experiments, and its TMF equal to B0 = 2.25 T. The algorithm reveals a reconstruction error of approximately 0.1% for the flux function. The results also indicate that for a Mach number at the major radius between 0.2 and 0.3, the maximum plasma current reaches 5.5 MA. Furthermore, the normalized beta and safety factor are around 3, the average poloidal beta is 0.8, the normalized inductance is 0.75, and the toroidal frequency (ω) at the major radius is 63 krad/s. These results are found in good agreement with experimental data. Additionally, the study provides a quantitative assessment of how the toroidal flow affects plasma parameters and demonstrates the relationship between poloidal beta and rotation velocity

Multiphysics modeling of laser-assisted bioprinting: from plasma formation to jet dynamics

A. Zerradi — 2025-11-01

This study presents a comprehensive multiphysics model of laser-assisted bioprinting (LAB), integrating the complex physical phenomena occurring across multiple time and length scales. Our model encompasses the laser-matter interaction, plasma formation, cavitation bubble dynamics, and fluid mechanics of jet formation. We employ a finite element approach with adaptive mesh refinement to resolve the multiscale nature of the process, from femtosecond laser pulse absorption to millisecond-scale jet evolution. The model accurately captures the non-linear absorption mechanisms, including multiphoton ionization and avalanche ionization, leading to plasma formation with electron densities exceeding 10²⁰ cm^-3 and temperatures reaching 5000 K. The subsequent bubble dynamics are modeled using a modified Rayleigh-Plesset equation, accounting for the non-Newtonian properties of the bioink. Our simulations reveal a maximum bubble radius of 45 μm and collapse time of 4.2 μs, in excellent agreement with experimental observations. The jet formation phase is characterized by a maximum height of 46 μm and initial velocity of 30 m/s, with distinct acceleration, deceleration, and retraction phases. The model elucidates the complex energy transfer cascade from the initial laser pulse to the final jet formation, with approximately 7% of the initial laser energy ultimately contributing to jet kinetics. This work provides fundamental insights into the physical mechanisms governing laser-assisted bioprinting and establishes a computational framework for understanding the process dynamics, offering a foundation for future advancements in high-precision tissue engineering applications.

On the Lagrange's equilateral homographic flat motion of three bodies interacting with the Newton gravitational force

Eduardo Piña Garza — 2025-11-01

We present the equilateral three-body motion with three different masses according to Newton gravitational force, which was discovered by Lagrange, tracing conic trajectories. We will extend to several bodies the generalization of the equilateral triangle solution discovered by Lagrange. The flat n-body problem of several different masses can be solved in closed and elementary form if we assume that the polygon formed by several celestial bodies always remains similar to itself. The Lagrange proof was simplified by C. Caratheodory and we extend ´ without problem this proof to several bodies. The bodies move on a fixed plane with two independent coordinates: one rotation around the center of mass, and one radial expansion. At any time the position vector of each body is the same multiple of the acceleration vector of the body. Bodies move tracing similar conics with the pole of each conic at the center of mass. For the three-body Lagrange’s case, a rigid triangle function of the masses discovered by Simo, is described with very simple geometry. Which we should place in a particular position ´ imposed by the Lagrange’s solution. We present a set of mathematical properties which are not well known.

On the local energy conservation of a system of three unidirectionally coupled undamped forced Duffing oscillators and their dynamics

Israel Alonso Alvarado-López — 2025-11-01

The Duffing oscillator is a well-established model with broad applications in physics, engineering, and biological systems. This study examines a system of three undamped, non-autonomous Duffing oscillators arranged in a unidirectionally coupled ring configuration. The model enables the exploration of intricate dynamical behaviors, including multistability, synchronization, and the onset of chaos. Local energy conservation is analyzed through integrals of motion and phase-space examination, considering various coupling strengths and natural frequency parameters. By applying the Milne-Pinney equations, the study identifies three conserved quantities—each associated with an oscillator—whose interdependence reflects the structural influence of the ring. The findings demonstrate how unidirectional coupling and non-autonomous forcing facilitate energy exchanges within the system, revealing that local energy conservation is not merely a consequence of global symmetries but rather emerges from the complex interplay of nonlinear interactions. This deeper perspective enhances the understanding of energy dynamics in coupled oscillatory systems.

Ab-initio calculation of optical properties of monolayer arsenene with substituted atoms

J. D. García-Aguilar — 2025-11-01

Ab initio DFT calculations were used to investigate how C, Ga, Ge, O, and Se doping modify the structural, electronic, and optical properties of arsenene. Our investigation has revealed that doping leads to substantial modifications in the electronic attributes and slight distortions in the crystal lattice, affecting bond lengths and angles. These modifications have driven to have tunable band gaps, which are vital for the development of nanoelectronic and optoelectronic technologies. Furthermore, we have delved into the optical properties of doped arsenene by calculating the dielectric function within the energy window of 0 to 10 eV. Our findings demonstrate that doping results in shifts in the absorption edges and changes in the refractive index. Overall, our results provide valuable insights into the tunability of electronic and optical characteristics in doped arsenene, paving the way for its implementation in advanced technological applications.

Spectroscopic characterization and high antibacterial activity of silver nanoparticles functionalized Alpaca fibers

Héctor Aníbal Félix Quintero — 2025-11-01

Using a simple chemical solution synthesis method, silver nanoparticle-functionalized alpaca fibers were prepared. Special attention was paid to three natural colors of alpaca fibers: white, brown, and black, for the study of absorbance, excitation, emission, Raman, and FTIR spectra. The alpaca fibers at higher silver concentrations exhibited an efficient SERS effect on the melanin molecule, with two bands centered at 1568 and 1336 cm⁻¹. The first band originated from the in-plane stretching of the aromatic rings, and the latter from the linear stretching of the C=C bonds within the rings. This molecule increases antibacterial capacity by enhancing the presence of Ag+ ions. The fibers treated with silver showed excellent antibacterial activity against Escherichia coli ATCC 25922.

Fisher information and quantum entropies of a 2D system under a pair of non-central scalar and vector potentials

Ahmed Becir — 2025-11-01

In this study, we examine a 2 dimensional system influenced by a non-central potential consisting of a Kratzer potential with a dipole moment, along with a vector potential of the (AB) effect. We explore various information-theoretic measures, including Fisher information, Shannon entropy, Tsallis entropy, and Rényi entropy. Our numerical results show that the Fisher information increases with an increase in dissociation energy and decreases with rising dipole moment, Aharonov–Bohm potential strength, and both the radial and angular quantum numbers. In contrast, the Shannon entropy, the Tsallis entropy, and the Rényi entropy decrease with rising dissociation energy, while they increase with an increase in dipole moment, Aharonov–Bohm potential strength, as well as the principal and angular quantum numbers. These observations collectively indicate that the precision and localization of particles in space are enhanced by the increasing of the dissociation energy and reduced when the dipole moment, Aharonov–Bohm potential strength, and both the radial and angular quantum numbers increase.

Nonlinear optical behavior of chloro antimony (III) hexadecafluorophthalocianinato thin films characterized by Z-scan technique

Gustavo Mendoza-Torres — 2025-11-01

In this work, two chloro antimony (III) hexadecafluorophthalocianinato thin films, with two different concentrations were deposited on glass substrates, Z-scan experiments at the wavelength of 633 nm (HeNe laser) and different optical powers were carried out. The results were fitted with the Photo-Induced Lens and Nonlocal theoretical models. Negative and non-local nonlinear optical response behavior is reported.

A novel symmetry property of the Fourier transform

Rafael G. González- Acuña — 2025-11-01

This manuscript presents and proves a reciprocity relation involving the Fourier transforms of a pair of square-integrable functions, expressed as a bilinear map. This reciprocity relation reveals a deep symmetry between the time (or spatial) and frequency domains. We explore its implications in theoretical and applied contexts such as signal processing, quantum mechanics, and computational physics. Additionally, we discuss the role of this relation in the bilinear nature of Fourier analysis.