Physics Open最新文献

{"title":"The inverse magnetocaloric effect in YBa2Cu3O7-δ based phenomenological modelling","authors":"Mahmoud A. Hamad ,&nbsp;Hatem R. Alamri","doi":"10.1016/j.physo.2026.100429","DOIUrl":"10.1016/j.physo.2026.100429","url":null,"abstract":"<div><div>A phenomenological model (PM) is handled to predict magnetocaloric effect (MCE) of YBa₂Cu₃O_7-δ (YBCO) under 0.01 T magnetic field, concluding MCE parameters from simulation of the isofield thermo-magnetization curve of YBCO from 0 to 0.01 T. The magnetic entropy change takes positive values with full-width at half-maximum of 17.8 K, indicating the MCE of YBCO is an inverse type. It is recommended that YBCO is suitable for use at various temperatures as an effective material of MR, covering temperatures ranging from 60 to 95 K. The obtained values are compared with some reported magnetic materials and show that YBCO could be a favorable material for cryogenic magnetic refrigeration.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"27 ","pages":"Article 100429"},"PeriodicalIF":1.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148184881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dissolution of Baganuur coal analyzed by electron paramagnetic resonance spectroscopy","authors":"Munkhtsetseg Sambuu,&nbsp;Uilstuguldur Enkhbaatar,&nbsp;Shilagardi Golimensee","doi":"10.1016/j.physo.2026.100431","DOIUrl":"10.1016/j.physo.2026.100431","url":null,"abstract":"<div><div>Experimental studies have been conducted on the solubility of subbituminous coal from Baganuur, Mongolia, in solutions of conventional organic pyridine and modern, “green”, imidazolium-based ionic liquid [Bmim]Cl.</div><div>EPR spectroscopy is employed to investigate the original material and its extraction process.</div><div>Inertinite-rich Baganuur coal consists of a highly reactive organic fraction of high-gravity ashery residues. As-received coal gives a slightly asymmetric, singlet EPR spectrum at room temperature. After processing with solvents, the inner structure in the spectrum decomposed depending on the used solvent.</div><div>Various forms of free radical generation were noted. Auxiliary experiments are conducted simultaneously for resolving the type of the radical. Among those radicals, the surface oxygen reactive radicals are revealed and annihilated by mild experimental conditions. In-depth analysis from EPR regarding microwave power dependence and line shape illustrates structural changes occurring during the solubility of coal.</div><div>Depending on the solvents used, the newly formed charge-transfer complex remained stable. Analysis of line shape reveals the radical interaction, which is subject to Gaussian and Lorentzian laws. The solubility restriction of studied coal in the solvent is a result of the subsequent formation of radicals as a result of Lorentz lines.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"27 ","pages":"Article 100431"},"PeriodicalIF":1.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148184751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design optimization of a C/X-band metasurface–DGS microstrip antenna using machine learning","authors":"Md. Bipul Islam,&nbsp;A.N.M. Shihab Uddin,&nbsp;Samiul Bashir,&nbsp;Pronab Kumar Paul,&nbsp;Md. Firoz Ahmed,&nbsp;M. Hasnat Kabir","doi":"10.1016/j.physo.2026.100419","DOIUrl":"10.1016/j.physo.2026.100419","url":null,"abstract":"<div><div>Microstrip patch antennas (MPAs) typically suffer from limited bandwidth and low gain in C- and X-band applications. This study presents a machine learning (ML)-assisted antenna design that integrates an elliptical metasurface with a defected ground structure (DGS) to enhance performance. The antenna is implemented on a low-loss F4B substrate (εᵣ = 2.65, tan δ = 0.0015, thickness = 1.6 mm) and excited using a 50 Ω coaxial probe feed. A data-driven optimization framework is developed using two supervised regression models: an artificial neural network (ANN) and a random forest (RF) regressor. These models are trained on 100 full-wave electromagnetic simulations (CST Microwave Studio) to predict return loss (S₁₁), impedance bandwidth, voltage standing wave ratio (VSWR), gain, and directivity. Both models achieve a coefficient of determination (R²) greater than 0.97 and a mean absolute error below 1.5%, demonstrating high predictive accuracy. The integration of ML with electromagnetic design is a key strength of this work. The ML-optimized antenna exhibits simulated performance of −53 dB return loss, 47.6% impedance bandwidth (5.68–9.24 GHz), VSWR of 1.00, peak gain of 4.91 dBi, and radiation efficiency of 98.8%. Compared with similar metasurface-based MPAs, this represents a bandwidth improvement of 17–40%. The ML-assisted approach reduces optimization time by approximately 88% relative to conventional parametric sweeps. All results are simulation-based; experimental validation has not yet been performed. The proposed design is suitable for broadband applications including 5G communication, satellite links, and radar systems. Future work will focus on experimental validation, multilayer gain enhancement, and extension to millimeter-wave frequencies.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"27 ","pages":"Article 100419"},"PeriodicalIF":1.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147849679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optical absorption, Raman spectroscopy, and surface morphology of Dy3Fe5O12 single crystals","authors":"Mirzo Sharipov ,&nbsp;Dilshod Hayitov ,&nbsp;Shakhobiddin Fayziev ,&nbsp;Abdullo Ahadov ,&nbsp;Davron Dzhuraev","doi":"10.1016/j.physo.2026.100420","DOIUrl":"10.1016/j.physo.2026.100420","url":null,"abstract":"<div><div>The optical properties of Dy₃Fe₅O₁₂ single crystals have been investigated using a combined approach comprising optical absorption spectroscopy, Raman spectroscopy, and atomic force microscopy. The absorption spectra measured in the 200–1100 nm range reveal a pronounced separation between high-energy and low-energy electronic excitations. The ultraviolet–visible region is dominated by intense electronic transitions within the Fe–O sublattice, which may include both ligand-to-metal charge-transfer and correlation-driven intersite contributions. In contrast, the near-infrared region exhibits weak absorption features attributed to intra-ionic 4f–4f transitions of Dy³⁺ ions. Raman spectroscopy confirms the high structural quality of the crystals through the presence of well-resolved phonon modes with low linewidths, while atomic force microscopy demonstrates a morphologically homogeneous surface with no periodic modulation that could induce optical artifacts. These results collectively support the interpretation that the observed spectral features originate predominantly from intrinsic bulk electronic and lattice properties. The combined analysis reveals a clear decoupling between Fe–O-derived electronic excitations and localized Dy³⁺ states, which dominate different spectral regions. This separation provides a consistent framework for interpreting the optical response of rare-earth iron garnets. The results also highlight the limitations of room-temperature measurements for resolving the microscopic origin of high-energy transitions, indicating the need for further temperature- and polarization-dependent studies.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"27 ","pages":"Article 100420"},"PeriodicalIF":1.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147945168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ab initio study of the effect of substitutional impurities Mo and C on the physico mechanical properties of ZrB2-based solid solutions","authors":"Nataliia Rozhenko,&nbsp;Liubov Ovsiannikova,&nbsp;Valerii Kartuzov,&nbsp;Serhii Ivanov","doi":"10.1016/j.physo.2026.100421","DOIUrl":"10.1016/j.physo.2026.100421","url":null,"abstract":"<div><div>A predictive computational approach has been developed and implemented to evaluate the bulk modulus (<em>B</em>) and single-crystal hardness (<em>H</em>_<em>V</em>) of ZrB₂-based solid solutions containing substitutional Mo and/or C impurities. By employing first-principles studies of isolated atomic clusters as representative structural fragments, this method provides a cost-effective alternative to expensive trial-and-error experimental synthesis of complex ultra-high-temperature ceramics (UHTCs). The validity of the model is confirmed by its high predictive accuracy, showing close agreement with experimental benchmarks for the matrix and related doped systems. For the first time, a quantitative assessment of the synergistic effect of Mo and C co-doping on the intrinsic mechanical properties of the ZrB2 crystal lattice is presented. The results reveal that a significant enhancement in bulk modulus (11–13 %) and hardness (16–17 %) is achieved at a total impurity concentration of approximately 15–17 at.%. These findings establish the intrinsic mechanical limits of the doped lattice, providing a theoretical baseline for the design and development of UHTCs where Mo and C are used for activated sintering.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"27 ","pages":"Article 100421"},"PeriodicalIF":1.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147945108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dependence of neutron supermirror reflectivity on substrate roughness","authors":"Zhuo Li ,&nbsp;Zeying Cai ,&nbsp;Ruimin Yan ,&nbsp;Shun Xia ,&nbsp;Jun Xiong ,&nbsp;Wenxin Peng ,&nbsp;Yanyan Wu ,&nbsp;Le Kang","doi":"10.1016/j.physo.2026.100424","DOIUrl":"10.1016/j.physo.2026.100424","url":null,"abstract":"<div><div>Substrate roughness criteria for high reflectivity supermirror coatings have been developed to enable domestic fabrication of neutron guides for the China Spallation Neutron Source. Systematic experiments correlating white light interferometry measurements with neutron reflectivity data demonstrate that, under current CSNS coating conditions, the RMS roughness over an <span><math><mrow><mn>88</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> field of view should be below 0.2 nm to achieve <span><math><mo>&gt;</mo></math></span>93% reflectivity at <span><math><mrow><mi>m</mi><mo>=</mo></mrow></math></span> 2, while a roughness approaching 0.15 nm is preferred to reach <span><math><mo>&gt;</mo></math></span>91% at <span><math><mrow><mi>m</mi><mo>=</mo></mrow></math></span> 2.5. Power spectral density analysis provides more detailed surface characterization than roughness values alone, offering a reliable benchmark for polishing and coating process optimization. These findings establish practical qualification indicators for collaboration between substrate manufacturing and coating deposition, thereby advancing the batch production of high performance neutron supermirror optics.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"27 ","pages":"Article 100424"},"PeriodicalIF":1.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147995400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal and flow characteristics of ternary hybrid nanofluids in a rotating magnetohydrodynamic channel","authors":"I.O. Okunade,&nbsp;O.A. Ajala,&nbsp;A.O. Akindele,&nbsp;A.D. Ohaegbue,&nbsp;M.O. Afolabi","doi":"10.1016/j.physo.2026.100416","DOIUrl":"10.1016/j.physo.2026.100416","url":null,"abstract":"<div><div>This paper investigates the flow and heat transfer of ethylene glycol-based nanofluids, dual hybrid nanofluids, and ternary hybrid nanofluids in a rotating channel under the influence of a magnetic field. The nanofluids are composed of nanoparticles of alumina, iron oxide, and zirconium oxide. The study incorporates the effects of rotation, suction or injection, heat generation, and thermal radiation. The governing highly nonlinear partial differential equations are transformed into ordinary differential equations using similarity variables and solved numerically with the Chebyshev Collocation Method in MATHEMATICA 11.3. Results show that suction increases temperature and velocity, whereas magnetic effects reduce velocities while enhancing temperature distribution. The ternary hybrid nanofluid demonstrates superior thermal performance compared to the dual hybrid nanofluid and the single-component nanofluid, highlighting its potential for efficient thermal management in rotating magneto-hydrodynamic systems.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"27 ","pages":"Article 100416"},"PeriodicalIF":1.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147798106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design of artificial neural network to predict heat and mass transfer of Casson fluid over a shrinking curve: A stability analysis","authors":"Masood Khan ,&nbsp;Mudassar Qamar ,&nbsp;Jawad Ali ,&nbsp;Irsa Hanif ,&nbsp;Ebrahem A. Algehyne ,&nbsp;Ibrahim Alraddadi","doi":"10.1016/j.physo.2026.100422","DOIUrl":"10.1016/j.physo.2026.100422","url":null,"abstract":"<div><div>This investigation focuses on a novel examination of the Darcy-Forchheimer model of Casson fluid under slip constraints via a penetrable shrinking curve. The significance of variable thermal conductivity, viscous dissipation, multiple slip conditions and chemical reactions are uniquely incorporated. The governing PDEs are truncated into ODEs under the implementation of similarity variables. To train the solution data for reliable predictions under changing factor values, artificial neural networks (ANNs) are created, and a dual solution analysis is also conducted through the bvp4c approach. The major findings represent that the first solution is stable and the second is unstable via temporal stability analysis. The ANN's efficacy as a quick and precise surrogate model for assessing energy transfer performance in intricate Casson fluid systems was confirmed by the close match between its prediction and the numerical data. The variations in curvature factor result in reduced shear stress and mass transportation rates. Furthermore, flow, thermal, and mass transfer are estimated using regression analysis, and the average estimation was accurately predicted by an artificial neural network model (R = 1).</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"27 ","pages":"Article 100422"},"PeriodicalIF":1.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147995398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comprehensive performance comparison and applicability analysis of bidirectional flow passage pump device based on hub ratio under multi-operating conditions","authors":"Yi Yang ,&nbsp;Zhaohui Shen ,&nbsp;Wei Shi ,&nbsp;Xuejiao Huang ,&nbsp;Xianglin Xia ,&nbsp;Lijian Shi ,&nbsp;Wenyu Xia ,&nbsp;Muzi Xue","doi":"10.1016/j.physo.2026.100399","DOIUrl":"10.1016/j.physo.2026.100399","url":null,"abstract":"<div><div>To investigate the applicability of modified pump unit designs in actual pumping station projects, this study employs a combined approach of numerical simulation and model testing. It compares the hydraulic performance of pump units with different hub ratios, analyzes the patterns of internal flow losses under various configurations, and proposes operational conditions for different hub ratios in practical pumping station engineering. Research indicates that the hub ratio significantly influences the pump unit's high-efficiency range, hydraulic loss distribution in the discharge flow path, and cavitation performance. At a hub ratio λ = 0.4, the pump unit exhibits the widest high-efficiency range, shifted toward higher flow rates by approximately 20% <em>Q</em>_<em>d</em>. Pump units with smaller hub ratios demonstrate higher hydraulic efficiency under low-head, high-flow conditions. At a hub ratio λ = 0.467, the pump unit's high-efficiency zone shrinks and shifts toward lower flow rates by approximately 15% <em>Q</em>_<em>d</em>, while cavitation performance improves under high-head, low-flow conditions. Hydraulic losses in the pump assembly primarily occur in the discharge flow passage and guide vane assembly. Under design conditions, hydraulic losses in the discharge flow passage account for approximately 73.43% of total hydraulic losses, while those in the guide vane assembly constitute about 22.01%. Entropy production analysis based on the turbulent dissipation theory shows that the larger the hub ratio, the smaller the high entropy production regions at the outlet guide cone and the diffuser, thereby reducing the hydraulic loss in the outlet passage. Therefore, the selection of the hub ratio must be comprehensively determined based on the actual operating conditions of the pump station (head and flow requirements). The findings of this study provide a theoretical basis for the optimized design of bidirectional flow passage pump units.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"27 ","pages":"Article 100399"},"PeriodicalIF":1.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147798104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and calculation of short-wavelength interband cascaded Type-II superlattices photodetectors","authors":"Yanan Du ,&nbsp;Yun Xu ,&nbsp;Tuo Li ,&nbsp;Changhong Wang ,&nbsp;Yuan Zhao ,&nbsp;Kejian Zhu ,&nbsp;Kang Su","doi":"10.1016/j.physo.2026.100417","DOIUrl":"10.1016/j.physo.2026.100417","url":null,"abstract":"<div><div>Type-II superlattices (T2SLs) materials have attracted widespread attention in the field of photodetectors due to their advantages such as tunable bandgap, large electron effective mass, and low Auger recombination rate. This paper investigated the band structure of T2SLs interband cascade infrared photodetectors (ICIP), designed a five-stage ICIP device structure satisfying current matching conditions, and calculated key optoelectronic performance parameters including absorption coefficient, quantum efficiency, specific detectivity, and high-frequency 3 dB bandwidth. The calculation results demonstrate that T2SLs ICIP exhibit excellent optoelectronic characteristics, making them suitable for applications in optical communication, multi-color infrared detection, and related fields.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"27 ","pages":"Article 100417"},"PeriodicalIF":1.4,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147945169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}