Results in Physics最新文献

{"title":"Non-reciprocity of energy transfer derived from cubic stiffness-induced nonlinear phenomena","authors":"Na Kong ,&nbsp;Min Sun ,&nbsp;Jianen Chen","doi":"10.1016/j.rinp.2025.108290","DOIUrl":"10.1016/j.rinp.2025.108290","url":null,"abstract":"<div><div>Introducing purely nonlinear elastic elements can induce rich dynamic behaviors, such as bifurcations, jumps and isolated resonance curves, to linear systems. Therefore, these elements are suitable for constructing strong non-reciprocity of vibration energy transfer. First, the energy transfer along reciprocal directions in a three-degree-of-freedom system is investigated, where three oscillators are connected by cubic springs. The semi-analytical solutions of the system are obtained using the complexification-averaging method and the least squares method. The results are compared against numerical solutions obtained by the Runge-Kutta method. The excitation amplitude range that produces strong non-reciprocity of vibration energy is analyzed. The jump phenomenon under combined excitation is investigated, and a trigger method for constructing non-reciprocity using an impulse is proposed. Then, an oscillator chain with cubic stiffness and scaling parameters is embedded into a multi-degree-of-freedom linear oscillator system to further explore the effect of cubic stiffness. Energy transfer along two directions is compared by exciting the leftmost oscillator and the rightmost oscillator. Moreover, the trigger effect of the impulse on non-reciprocity is demonstrated. The results show significant differences in vibration energy transfer within three distinct frequency bands. The critical points between reciprocal and non-reciprocal states are obtained, and the three stages of reciprocity related to excitation amplitude are analyzed. Lastly, the modulation effect of the cubic stiffness on non-reciprocity is conducted by comparing the energy of the output oscillator.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"73 ","pages":"Article 108290"},"PeriodicalIF":4.4,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143918014","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":"T-gate with dual dielectric layer for p-GaN/AlGaN/GaN HFETs: Suppressed gate leakage current and increased gate voltage range","authors":"Min-Gi Jeong ,&nbsp;Gökhan Atmaca ,&nbsp;Ho-Young Cha","doi":"10.1016/j.rinp.2025.108294","DOIUrl":"10.1016/j.rinp.2025.108294","url":null,"abstract":"<div><div>In this paper, a T-shaped gate with a dual dielectric layer is proposed for enhancement-mode p-GaN/AlGaN/GaN heterojunction field-effect transistors (HFETs), designed to reduce gate leakage current and improve gate forward breakdown voltage. The proposed dual dielectric layer, comprising Al₂O₃ and SiO₂ films, modulates the energy band structure at the gate edge to suppress the hole injection from the gate metal to the p-GaN layer. As a result, the p-GaN/AlGaN/GaN HFET with the proposed T-shaped gate demonstrated a significantly reduced gate leakage current of ∼ 10^-7 A/mm at V_GS = 8 V and a substantially higher gate forward breakdown voltage of 16 V, compared to a conventional structure with a gate leakage current of ∼ 10^-3 A/mm at V_GS = 8 V and a gate forward breakdown voltage of 8.5 V. Additionally, the off-state breakdown voltage of the proposed device was noticeably improved. These results suggest that the proposed dual dielectric configuration offers a promising approach to overcoming the limited gate voltage range of conventional p-GaN/AlGaN/GaN HFETs, thereby enhancing device reliability.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"74 ","pages":"Article 108294"},"PeriodicalIF":4.4,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143922246","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":"Thermosolutal convection and entropy generation in hybrid nanofluids: FEM and ANN analysis of a magnetized wavy enclosure","authors":"Noor Zeb Khan ,&nbsp;Muhammad Salim Khan ,&nbsp;A.S. Shflot ,&nbsp;M.Y. Malik","doi":"10.1016/j.rinp.2025.108291","DOIUrl":"10.1016/j.rinp.2025.108291","url":null,"abstract":"<div><div>This study investigates the thermosolutal convection and entropy generation in a magnetohydrodynamic (MHD) hybrid nanofluid-filled enclosure featuring wavy vertical walls and a centrally placed star-shaped cylinder. The problem addresses the critical need to optimize heat and mass transfer in engineering systems, such as thermal management, energy storage, and electronic cooling. A hybrid nanofluid composed of alumina (<span><math><mrow><mi>A</mi><msub><mi>l</mi><mn>2</mn></msub><msub><mi>O</mi><mn>3</mn></msub></mrow></math></span>) and copper (<span><math><mrow><mi>C</mi><mi>u</mi></mrow></math></span>) nanoparticles in water is analyzed using the Finite Element Method (FEM) via COMSOL Multiphysics, complemented by an Artificial Neural Network (ANN) model to predict the Nusselt number and validate results. Key findings reveal that increasing the Rayleigh number (Ra) from 10³ to 10⁵ enhances the average Nusselt number (Nu_Avg) by<!--> <!-->16.27 %<!--> <!-->and total entropy generation (E_Total) by<!--> <!-->93.53 %, driven by intensified buoyancy-driven convection. Conversely, a stronger magnetic field (Ha = 50) suppresses fluid motion, reducing (Nu_Avg)<!--> <!-->by<!--> <!-->18.03 %<!--> <!-->and Sherwood number (Sh_Avg) by<!--> <!-->10.83 %, while increasing E_Total <!-->by<!--> <!-->80.83 %<!--> <!-->due to Lorentz forces. Hybrid nanoparticles (2 % volume fraction) improve (Nu_Avg) by<!--> <!-->6.63 %<!--> <!-->compared to pure fluid, demonstrating their thermal enhancement potential. The Lewis number (Le) and buoyancy ratio (N) significantly influence mass transfer, with<!--> <!-->(Sh_Avg) rising by<!--> <!-->41.60 %<!--> <!-->at (Le = 10)<!--> <!-->and<!--> <!-->32.90 %<!--> <!-->at<!--> <!-->(N = 10). The ANN model achieves exceptional accuracy (R = 1, MSE = 2.47 × 10⁻⁹) in predicting thermal behavior, reducing computational effort. Novelty lies in the combined analysis of hybrid nanofluids, star-shaped geometry, and MHD effects using FEM-ANN integration a configuration unexplored in prior literature. This work provides actionable insights for designing energy-efficient systems with optimized entropy generation and enhanced thermal performance.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"73 ","pages":"Article 108291"},"PeriodicalIF":4.4,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143912506","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":"Thermal analysis of ternary hybrid nanofluid flow in convergent/divergent channel using Box-Behnken design of response surface methodology","authors":"Ibrahim Mahariq ,&nbsp;C.M. Mohana ,&nbsp;B. Rushi Kumar ,&nbsp;Kezzar Mohamed ,&nbsp;Mohamed Rafik SARI ,&nbsp;Hamiden Abd El-Wahed Khalifa ,&nbsp;Sunitha Nagarathnam","doi":"10.1016/j.rinp.2025.108293","DOIUrl":"10.1016/j.rinp.2025.108293","url":null,"abstract":"<div><div>Convergent/divergent channels represent a critical advancement in thermal management systems, offering enhanced heat transfer capabilities through geometrically optimized flow paths. This study investigates the thermal and hydrodynamic characteristics of UO₂-ZnO-Fe₃O₄/EG-water ternary hybrid nanofluid in rotating convergent/divergent channels with magnetohydrodynamic and radiation effects, a critical area for enhancing heat transfer efficiency in modern thermal management systems. Employing the Runge-Kutta-Fehlberg method coupled with a Box-Behnken design approach, we analyzed how key parameters affect flow behavior and heat transfer performance. The numerical simulations reveal that increasing the nanoparticle volume fraction from 0.01 to 0.06 enhances the Nusselt number by 27.3 %, while an increase in the magnetic parameter reduces the friction coefficient by 41.2 %. The Reynolds number demonstrates a strong positive correlation with the Nusselt number (R² = 0.978). Maximum heat transfer (Nu = 33.4859) achieved at: α = 1°, Re = 40, φ = 3 %, Ha = 50, Rd = 1, Kn = 0.04, De = 0.5, Ro = 50, ε = 0, λ = 0.5 whereas a minimum flow resistance (Cf = -2.60454) occurred at: α = -3°, Re = 60, φ = 6 %, Ha = 25, Rd = 1, Kn = 0, De = 0.5, Ro = 50, ε = 0.2, λ = 0.5. For the convergent channel configuration (α = -3°), the friction coefficient was 28.3 % higher than in the divergent channel (α = 5°) under identical flow conditions. This work advances the field beyond previous studies by comprehensively analyzing the synergistic effects of rotation, magnetohydrodynamic, radiation, and channel geometry on the performance of ternary hybrid nanofluids, providing crucial insights for designing more efficient thermal systems in electronics cooling, heat exchangers, and industrial processing applications.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"74 ","pages":"Article 108293"},"PeriodicalIF":4.4,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143922248","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":"Electron-phonon interactions and Helmholtz free energy in confined systems: Advancing low-dimensional superconductors for quantum technologies","authors":"Nitin Pratap Singh ,&nbsp;Kusum Lata ,&nbsp;Linga Reddy Cenkeramaddi","doi":"10.1016/j.rinp.2025.108270","DOIUrl":"10.1016/j.rinp.2025.108270","url":null,"abstract":"<div><div>The thermodynamic and superconducting properties of low-dimensional superconductors are profoundly influenced by electron–phonon interactions, which play a critical role in determining the Helmholtz free energy. Therefore, the quantitative study of Helmholtz free energy using electron–phonon interactions in low-dimensional superconductors is essential to comprehending and improving superconducting materials, which are also the building blocks of developing quantum technologies. This article presents a quantitative analysis of our theoretically developed model with the impact of electron–phonon coupling on the Helmholtz free energy in low-dimensional superconductors. Using Green’s function methods and advanced many-body theory, we thoroughly examine the changes in the free energy landscape caused by changes in electron–phonon coupling strengths, temperature variation, effects of defects, and system dimensionality with the confinement phenomenon. The analysis also encompasses the behavior of electron–phonon interactions in quantum wells, offering insights into energy confinement and the effects of temperatures. The findings indicate notable changes in thermodynamic properties, especially in systems characterized by reduced dimensionality with the confinement of electrons in one dimension. The findings also underscore the significant impact of electron–phonon interactions on enhancing superconducting performance and establishing a framework for customizing superconducting material properties. The proposed quantitative model based on Helmholtz free energy and electron–phonon interactions provides a powerful framework for exploring the properties of low-dimensional superconductors, especially as they relate to practical applications in quantum technology.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"73 ","pages":"Article 108270"},"PeriodicalIF":4.4,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143912508","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":"Delocalized Ag−Ag dimer rattling mode contributes to reduced thermal conductivity and enhanced thermoelectric performance in AgAs2","authors":"Jie Zhang ,&nbsp;Minghao Zhan ,&nbsp;Wending Wang ,&nbsp;Xiaohong Xia ,&nbsp;Yun Gao ,&nbsp;Zhongbing Huang","doi":"10.1016/j.rinp.2025.108285","DOIUrl":"10.1016/j.rinp.2025.108285","url":null,"abstract":"<div><div>Layered thermoelectric materials inherently feature a decoupling of electron and phonon transport, attributed to the high electrical conductivity within the covalent atomic layers and the increased phonon scattering at the layer boundaries. However, the weak atomic interactions along the out-of-plane direction present a considerable obstacle in enhancing the thermoelectric performance of these materials. In this work, we employ RuAs₄ (FeAs₄), SrAs₄ (CaAs₄), and AgAs₂ (CuAs₂) as representative compounds to theoretically explore the influence of bonding characteristics on the carrier transport in quasi-layered structures. We find that, in comparison to RuAs₄ (FeAs₄) with a similar atomic mass and crystal structure, the room temperature lattice thermal conductivity can be dramatically decreased from 10.2 (5.6) W/mK to 0.83 (1.69) W/mK in SrAs₄ (CaAs₄). This reduction is linked to the weak ionic interaction between the covalently bonded As layers and the Sr (Ca) atoms, resembling a rattling model that effectively scatters heat-conducting acoustic phonons. Conversely, the subvalent Ag₂ dimers and delocalized Ag−As bonds in AgAs₂ ensure rational electrical transport while preserving significant lattice anharmonicity due to the dimer clusters’ rattler-like behavior. Coupled with an enhanced Seebeck coefficient resulting from the elevated valence band degeneracy, we predict an p-type average thermoelectric ZT of 2.8 at 400 K. Our results provide an approach for modulating carrier transport in layered thermoelectrics via atomic or cluster intercalation, potentially serving as a guide for identifying novel thermoelectric materials.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"73 ","pages":"Article 108285"},"PeriodicalIF":4.4,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143912505","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":"Revisiting the effect of point defects on the decay of the longitudinal optical mode in semiconductors","authors":"Julian Anaya","doi":"10.1016/j.rinp.2025.108268","DOIUrl":"10.1016/j.rinp.2025.108268","url":null,"abstract":"<div><div>In a classic 2002 paper published by P.G. Klemens a theoretical analysis of the effect of point defects on the decay of the longitudinal optical mode in semiconductors was derived. The defect-induced phonon decay rate was analysed using convolution methods and second-order perturbation theory. In re-examining the derivation of these results, a critical error in the evaluation of an integral has been found, which is central to the main finding of the model. This letter demonstrates that the miscalculation leads to an incorrect scaling of the defect-induced broadening. In addition, a corrected derivation of the second-order perturbation result is given, yielding an amended expression for the optical phonon decay rate that aligns more closely with the expected physical behaviour. The revised result has significant implications for the quantitative interpretation of Raman line widths in isotopic mixtures and impurity systems, thereby refining the theoretical framework for analysing optical phonon decay in defective crystals.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"73 ","pages":"Article 108268"},"PeriodicalIF":4.4,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143906389","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":"International Advisory Board","authors":"","doi":"10.1016/S2211-3797(25)00167-6","DOIUrl":"10.1016/S2211-3797(25)00167-6","url":null,"abstract":"","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"72 ","pages":"Article 108273"},"PeriodicalIF":4.4,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887749","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":"Dynamics of quantum correlations in four-qubit XXZ Heisenberg model with external magnetic field","authors":"Su-Bok Ri,&nbsp;Gwang-Jin Kim,&nbsp;Ha Kim,&nbsp;Hyok Pak","doi":"10.1016/j.rinp.2025.108286","DOIUrl":"10.1016/j.rinp.2025.108286","url":null,"abstract":"<div><div>In this paper we argue about the quantum correlation (quantum entanglement and geometric quantum discord) in four-qubit XXZ Heisenberg Model. Here, the influence of uniform magnetic field on the dynamics of quantum correlation in cases of the antiferromagnetism has been mainly investigated. According to the results, it has been illustrated that the role of the uniform magnetic field on the dynamics of quantum correlation depends on the selection of the initial state. Furthermore, geometric quantum discord exhibits greater robustness compared to quantum entanglement. Also results show that the max values of quantum correlations decrease and the duration of quantum entanglement sudden death gets longer as purity parameter decreases, and that exchange interaction can substantially make an effect on the dynamics of the quantum correlation.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"74 ","pages":"Article 108286"},"PeriodicalIF":4.4,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068731","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":"Numerical investigation of thin film flow over a porous, non-flat moving sheet with nonlinear kinematics","authors":"Naeem Ullah ,&nbsp;Wang Jian ,&nbsp;Dil Nawaz Khan ,&nbsp;Sana Ben Moussa","doi":"10.1016/j.rinp.2025.108260","DOIUrl":"10.1016/j.rinp.2025.108260","url":null,"abstract":"<div><div>Flow of viscous thin film has previously been studied over a flat, porous and moving plate, whereas, these investigations are carried out for particular cases of uniform and linearly variable injection, suction, stretching and shrinking velocities. Moreover, the mechanisms of injection/suction and stretching/shrining have been analyzed individually and jointly for such flows. The present simulation has generalized the steady flow models of viscous thin film over porous, stretching and shrinking sheet of nonuniform thickness. We explored new and multiple dimensions of classical problems of thin film flow and analyzed it. Here, we categorically emphasized on the steady nature and kinds of injection (suction) and moving velocities of the sheet, whereas, steady form and variable size of the sheet are also taken into account. We formed different variables and investigated nonlinear cases of steady nature and checked different options for the two components of velocity, defined at the surface of sheet, variable sizes of the thin film and that of sheet. By analyzing all possible cases, we identified exact similarities that allowed the system of partial differential equations and boundary conditions to be precisely converted into ordinary differential equations based on these new variables. The transformed equation of continuity has two dimensionless parameters, which show that mass can be added/removed to/from the flow regime through two sources i.e. mass can be added/removed to/from the system by <strong>(i)</strong> injection/suction through porous sheet <strong>(ii)</strong> condensation/evaporation into/from the free surface. The system of exact ordinary differential equations is solved by <em><strong>bvp4c</strong></em> technique. Whereas, exact solutions of the system are also found under some restrictions on the parameters value. Besides that the two solutions are exactly matched to each other. Moreover, the present simulations are completely matched with the previously published work of this type for appropriate choices of functions and parameters. Note that the strict behavioral changes in the velocity profiles and skin friction coefficient are observed by changing the sign of parameters.</div></div>","PeriodicalId":21042,"journal":{"name":"Results in Physics","volume":"73 ","pages":"Article 108260"},"PeriodicalIF":4.4,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143882294","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}