Chinese Journal of Physics最新文献

{"title":"Prediction of axial ratio using machine learning (ML) for a dual-band circularly polarized dielectric resonator antenna (DRA)","authors":"Sachin Kumar Yadav ,&nbsp;Anupma Gupta ,&nbsp;Vipan Kumar ,&nbsp;Dinesh Kumar Garg ,&nbsp;Ahmed J.A. Al-Gburi","doi":"10.1016/j.cjph.2025.07.008","DOIUrl":"10.1016/j.cjph.2025.07.008","url":null,"abstract":"<div><div>In this paper, an asymmetrical dielectric resonator antenna (DRA) is designed to achieve circular polarization at dual frequencies within the C-band (4–8 GHz) and X-band (8–12 GHz) ranges. A regression-based machine learning (ML) technique is employed to predict the antenna’s axial ratio. The DRA structure consists of three rectangular ceramic blocks with a uniform permittivity of 9.8 and is excited by a microstrip feedline. Two dielectric resonators (DRs) of different heights are placed on the same plane, while the third DR is positioned atop the first two with a 60° rotation, enabling a wide 3 dB axial ratio (AR) bandwidth across both bands. The antenna operates from 5.2 GHz to 12.0 GHz, achieving a 10 dB impedance bandwidth of 79%. The AR bandwidth (≤ 3 dB) spans two bands: 6.0–8.7 GHz (lower band) and 9.9–11.8 GHz (upper band). The antenna maintains a gain of over 4 dBi throughout the bandwidth. Additionally, the antenna is analyzed in an array configuration, and beam steering at 30° is demonstrated through simulation. A dataset comprising various antenna dimensions and their corresponding axial ratio values is generated using parametric sweep analysis. A supervised regression-based ML approach is then employed to predict the axial ratio at two circularly polarized frequencies: 7.2 GHz and 10.5 GHz. Several regression algorithms are tested, and the Extra Trees Regression model achieves the lowest prediction error and highest accuracy.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"96 ","pages":"Pages 1364-1384"},"PeriodicalIF":4.6,"publicationDate":"2025-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144632008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Constructing regular stepped helices confined in carbon nanotubes with junctions","authors":"Rui Wang ,&nbsp;Xueyin Yang ,&nbsp;Yunfang Li ,&nbsp;Xiaolin Zhao","doi":"10.1016/j.cjph.2025.07.004","DOIUrl":"10.1016/j.cjph.2025.07.004","url":null,"abstract":"<div><div>Molecular dynamics simulations have been performed to investigate the confinement of coaxial single-walled carbon nanotubes with different diameters connected by junctions (J-CNTs) on one-dimensional poly(para)phenylene (PPP) polymer chains. The PPP chains enter the J-CNTs spontaneously and display a stepped helical configuration taking J-CNTs as template. The dynamics process, the variation of the total potential energy including various energy components and the constructed stepped helix are studied to reveal the evolution of microstructure, formation and driving mechanism. Besides, the influence of diameter and length of J-CNTs, the length and chain number of PPP polymer, and the number of junctions on the helical insertion and the construction of stepped helices is deeper studied. The expected outcome provides novel strategies for designing nanoscale regular stepped helices from polymer chains and applied to nanodevices.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"96 ","pages":"Pages 1314-1328"},"PeriodicalIF":4.6,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144597508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiphase flow dynamics analysis in jet cavitation nozzles: a novel approach for optimizing oily sludge treatment efficiency","authors":"Hanshuo Yang ,&nbsp;Dexi Wang ,&nbsp;Yali Yang ,&nbsp;Jiuchuang Jiang ,&nbsp;Honglei Yu ,&nbsp;Shengdong Li ,&nbsp;Jinyuan Guo","doi":"10.1016/j.cjph.2025.07.003","DOIUrl":"10.1016/j.cjph.2025.07.003","url":null,"abstract":"<div><div>The mixed multiphase flow model, RNG (Re-normalization group) <em>k-ε</em> turbulence model and Schnerr and Sauer cavitation dynamics model were used to numerically simulate the flow field of a jet cavitation nozzle, and the influence of the nozzle structure on the cavitation intensity was studied. The actual effect of three types of throat diameter nozzles in the treatment of oily sludge was explored. The simulation results show that the cavitation effect is best when the nozzle throat diameter is 0.4 mm, the diffusion angle is 50°, the contraction length is 8 mm, and the diffusion length is 6 mm. The experimental results show that in the case of a nozzle with a throat diameter of 0.4 mm, the oil content of the oily sludge after cavitation is reduced from 24.9 % to 9.8 %, and the total petroleum hydrocarbon (TPH) content is reduced by 84.8 %.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"96 ","pages":"Pages 1303-1313"},"PeriodicalIF":4.6,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of non-conserved gravity theory and electric charge in constructing complexity-free stellar models: A novel approach under non-minimal coupling","authors":"Tayyab Naseer","doi":"10.1016/j.cjph.2025.06.024","DOIUrl":"10.1016/j.cjph.2025.06.024","url":null,"abstract":"<div><div>This study explores the application of complexity factor within the context of Rastall gravity, exploring its implications on a static spacetime admitting spherical symmetry associated with anisotropic fluids under an electromagnetic field. The field equations are derived for a static charged sphere that provides a foundational framework for analyzing gravitational effects in this non-conserved theory. The mass function is formulated by incorporating both fluid and geometric parameters, offering insights into how mass distribution affects spacetime curvature. Through orthogonal decomposition of the Riemann tensor, a set of scalar quantities is obtained, referred to the structure scalars, which serve as indicators of celestial complexity. One specific scalar is then specified as the complexity factor, i.e., <span><math><msub><mrow><mi>Y</mi></mrow><mrow><mi>T</mi><mi>F</mi></mrow></msub></math></span>, facilitating further analysis on its role in characterizing complex systems. The presence of unknowns in gravitational equations necessitates the imposition of constraints to facilitate their solution. To address this, <span><math><mrow><msub><mrow><mi>Y</mi></mrow><mrow><mi>T</mi><mi>F</mi></mrow></msub><mo>=</mo><mn>0</mn></mrow></math></span> alongside three distinct conditions are employed which yield diverse stellar models. A comprehensive graphical analysis is conducted using multiple values of the Rastall and charge parameters. Notably, the findings of this study align with those predicted by Einstein’s theory. More appealingly, the Rastall theory demonstrates its superiority in the presence of charge under model 2 when it is compared with the general theory of relativity.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"96 ","pages":"Pages 1212-1231"},"PeriodicalIF":4.6,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144570760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dark matter admixed relativistic stars: Structural properties and tidal Love numbers","authors":"Takol Tangphati ,&nbsp;Grigoris Panotopoulos ,&nbsp;Ayan Banerjee ,&nbsp;Anirudh Pradhan","doi":"10.1016/j.cjph.2025.06.023","DOIUrl":"10.1016/j.cjph.2025.06.023","url":null,"abstract":"<div><div>We study the impact of bosonic, self-interacting dark matter on structural properties and tidal deformabilities of compact stars. As far as the gravitational theory is concerned, we assume Einstein’s gravity in four dimensions with a vanishing cosmological constant. Regarding matter content, we consider a state-of-matter to a linear form of equation-of-state (EoS), while for dark matter we assume a quartic scalar potential, which implies a certain non-linear EoS obtained long time ago. Adopting the two-fluid formalism we integrate the structure equations as well as the Riccati equation for the metric even perturbations imposing appropriate initial conditions at the center of the stars and matching conditions at their surface. We compute the stellar mass and radius, factor of compactness and dimensionless deformability varying several free parameters of the model studied here. Tidal deformability and the corresponding tidal Love number determine the imprint of the underlying EoS within the signals emitted during binary coalescences, and it is expected to be altered due to the presence of dark matter inside the objects. We find that in all cases considered here, the dimensionless deformability of the canonical stellar mass remains lower than the upper bound, <span><math><mrow><msub><mrow><mi>Λ</mi></mrow><mrow><mn>1</mn><mo>.</mo><mn>4</mn></mrow></msub><mo>&lt;</mo><mn>800</mn></mrow></math></span>. We also look at the stability of these stars based on the Harrison–Zeldovich-Novikov criterion under various conditions. It is observed that the presence of dark matter implies significantly lower highest stellar mass, and also smaller and more compact stars for a given stellar mass.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"96 ","pages":"Pages 1329-1343"},"PeriodicalIF":4.6,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144597509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coupled electromagnetohydrodynamic and heterogeneous reactive solute transport in non-Newtonian third-grade fluid flow through a microchannel","authors":"Raju Sen,&nbsp;Kajal Kumar Mondal,&nbsp;Nabanita Dey,&nbsp;Rishi Raj Kairi","doi":"10.1016/j.cjph.2025.06.032","DOIUrl":"10.1016/j.cjph.2025.06.032","url":null,"abstract":"<div><div>In this work, we investigated the microfluidic solute dispersion in electromagnetohydrodynamics (EMHD) flow of third-grade fluid in parallel plates microchannel. On account of the complex non-linearity of the Navier-Stokes equation, a series solution is introduced for the derivation of an analytical expression for a velocity distribution. For microscale system design, optimizing surface area and mass transfer efficiency is crucial. Skin friction contours aid in this evaluation. Additionally, the time-dependent convection–diffusion equation is analyzed using Aris’s method of moments to formulate the moment equations, which are solved through an implicit finite difference scheme. The mean concentration distribution of the tracers is calculated using the first four central moments expressed in a Hermite polynomial. Moreover, the two-dimensional concentration distribution is represented using contour plots, with the analysis based on Gill’s work on asymptotic expansions. From our investigation, it is apparent that higher values of the third-grade parameters (<span><math><mi>σ</mi></math></span>) improve the non-Newtonian characteristics and result in an obstruction to solute transport in the microchannel. Strong boundary absorption significantly accelerates tracer depletion in the microchannel, leading to an exponential reduction in contaminant retention over time. A higher electric field leads to a strong electroconductive effect to facilitate the mobility and velocity of charged particles that interact intensively with the medium, resulting in increased mixing and improved solute transport. Such a system strongly affects the ion separation process based on both charge and size, so increasing the strength of conduction field separation becomes more efficient. The analysis presents a highly complex understanding of solute dispersion control through a microfluidic system, offering modern application of the mechanism in drug delivery, blood flow, lab-on-a-chip devices, and cell separation.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"96 ","pages":"Pages 1385-1409"},"PeriodicalIF":4.6,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144632010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coating with Newtonian fluid by a two-parameter blade family leading to exact dynamic and thermal solutions","authors":"Mustafa Turkyilmazoglu ,&nbsp;Abdulaziz Alotaibi","doi":"10.1016/j.cjph.2025.06.007","DOIUrl":"10.1016/j.cjph.2025.06.007","url":null,"abstract":"<div><div>This study utilizes mathematical analysis to explore the classic phenomenon of coating by a thin fluid layer between a blade and a moving substrate, with the aim of uncovering new blade functions. Through fluid flow analysis, we derive a two-parameter family of blade geometries encompassing the widely studied cases of simple planar and exponential blades. By solving the associated momentum, thermal, and pressure fields in closed-form, we obtain explicit expressions for key engineering quantities of interest, including pressure gradient, load, film thickness, drag, and Nusselt numbers on both the substrate and the blade. These analytical formulas provide powerful tools for designing blades that effectively influence the physical and mechanical processes of coating, ultimately determining the desired film thickness. For instance, our analysis reveals that convex blade geometries generate lower load and drag, while concave geometries offer smoother fluid contact, leading to thinner film thicknesses and enhanced heat transfer.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"96 ","pages":"Pages 1191-1202"},"PeriodicalIF":4.6,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144562901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Constraining radii and stability of neutron stars in 4D Einstein–Gauss–Bonnet gravity","authors":"N. Priyobarta ,&nbsp;Ksh. Newton Singh ,&nbsp;S.K. Maurya ,&nbsp;B. Mishra","doi":"10.1016/j.cjph.2025.06.022","DOIUrl":"10.1016/j.cjph.2025.06.022","url":null,"abstract":"<div><div>In this paper, we have investigated the effects of Gauss–Bonnet extension on Einstein gravity in 4-dimensions. Four different equation of state, namely SLy4, APR4, FPS and Togashi are considered. These equation of state are used to model the massive neutron stars like PSR J0740+6620, PSR J1959+2048, PSR J1810+1744, PSR J2215+5135 and GW190814, which are in the neutron star-black hole mass gap. We have calculated the mass and radius through the <span><math><mrow><mi>M</mi><mo>−</mo><mi>R</mi></mrow></math></span> curves for different values of the Gauss–Bonnet coupling parameter for four different equation of state to examine the upper limit of masses that fall within the mass gap. Our results show that the positive branch of <span><math><mi>α</mi></math></span> is suitable for explaining the existence of massive neutron stars in the mass gap. Bondi’s and static stability criteria confirm the stability of these massive neutron stars. In fact, an increase in Gauss–Bonnet coupling strength improves the stability of these massive neutron stars. Furthermore, the surface redshift of these massive neutron stars is below the maximum limit, i.e. <span><math><mrow><msub><mrow><mi>Z</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>≤</mo><mn>2</mn></mrow></math></span>. Finally, we have used the <span><math><mrow><mi>M</mi><mo>−</mo><mi>R</mi></mrow></math></span> curves with the observed masses to predict the radii of PSR J2215+5135, PSR J1959+2048, PSR J1810+1744, PSR J0740+6620 and GW190814 in general relativity and 4D Einstein–Gauss–Bonnet gravity. The predicted radii are in agreement with the constraints from the GW170817 event. Lastly, the maximum observed NS mass fits in the <span><math><mrow><mi>M</mi><mo>−</mo><mi>R</mi></mrow></math></span> curves, implying that the range of <span><math><mi>α</mi></math></span> should be somewhere around 0 to 5 <span><math><msup><mrow><mtext>km</mtext></mrow><mrow><mn>2</mn></mrow></msup></math></span>.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"96 ","pages":"Pages 1164-1177"},"PeriodicalIF":4.6,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144548350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An authenticated quantum dialogue scheme based on a one-way quantum channel","authors":"Jia-Hao Zhang ,&nbsp;Nian Xue ,&nbsp;Xin Huang ,&nbsp;Xiao-Ling Yu ,&nbsp;Wan-Cheng Liu ,&nbsp;Yong-Feng Dai","doi":"10.1016/j.cjph.2025.06.020","DOIUrl":"10.1016/j.cjph.2025.06.020","url":null,"abstract":"<div><div>In this paper, a novel authenticated quantum dialogue based on a one-way quantum channel is proposed. In this scheme, one party prepares some six-particle cluster states to send particle sequences to the other party via a one-way quantum channel; both parties perform quantum logic gate operations and measurement operations based on their respective secret information and speculate the initial state to announce the classical information; and finally, both parties decrypt to obtain the other party’s secret information and complete verification and authentication. The one-way quantum channel reduces the risk of transmission losses and errors, and authentication and verification enhance the robustness of this scheme. The feasibility of this scheme in quantum computing has been verified using the IBM Qiskit framework. The security analysis shows that this scheme can resist active and passive attacks from adversaries. In addition, we analyze the deviation of the output state of this scheme and demonstrate its security using formal verification methods under noise. The proposed scheme has relative efficiency and safety advantages over similar schemes.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"96 ","pages":"Pages 1116-1128"},"PeriodicalIF":4.6,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144524325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Goos-Hänchen-like effect in a gapped 8-Pmmn borophene-superlattice","authors":"Farhad Sattari ,&nbsp;Soghra Mirershadi","doi":"10.1016/j.cjph.2025.06.026","DOIUrl":"10.1016/j.cjph.2025.06.026","url":null,"abstract":"<div><div>The spin and valley-dependent Goos-Hänchen-like effect is studied theoretically in a gapped 8-<em>Pmmn</em> borophene superlattice under the external Rashba interaction. It has been observed that the Goos-Hänchen shift value for incident electrons with spin rotation is different from that without spin rotation. It is found that the Goos-Hänchen shift can be easily tuned by the Rashba strength, the number of the superlattice barriers, and the superlattice direction. The Goos-Hänchen shift is an oscillatory function of the Rashba and the energy gap strength, and the oscillatory behavior becomes clearer as the number of superlattice barriers increases. The spin-dependent Goos-Hänchen shift value and sign can be easily adjusted by the energy gap strength. With the increase in the number of superlattice barriers, the number of resonance peaks in the Goos-Hänchen shift increases. The Fano resonances can be observed in a gapped borophene superlattice under the external Rashba interaction.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"96 ","pages":"Pages 1203-1211"},"PeriodicalIF":4.6,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144570759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}