Pub Date : 2024-10-01DOI: 10.1016/j.cjph.2024.09.037
Ding-wei Huang
This study employs the Web of Science to examine patterns and trends in Academia Sinica’s scholarly publications, aiming to offer insights into both the quantity and quality of its research output. Initial findings reveal trends such as saturation in paper counts, increase in citation counts, diversification of journals, shifts in prominent research areas, widening disciplinary variances, and an evolving landscape of collaborations. Although the study does not differentiate among Academia Sinica’s three divisions, specific results related to the Institute of Physics will be addressed. Additionally, comparisons with other research institutes will be explored.
本研究利用 "科学网"（Web of Science）研究中央研究院学术出版物的模式和趋势，旨在深入了解其研究成果的数量和质量。初步发现的趋势包括论文数量饱和、引用次数增加、期刊多样化、主要研究领域转移、学科差异扩大以及合作格局不断变化。虽然这项研究没有对中央研究院的三个部门进行区分，但将讨论与物理研究所有关的具体结果。此外，还将探讨与其他研究机构的比较。
{"title":"Citation analysis on publications from Academia Sinica","authors":"Ding-wei Huang","doi":"10.1016/j.cjph.2024.09.037","DOIUrl":"10.1016/j.cjph.2024.09.037","url":null,"abstract":"<div><div>This study employs the Web of Science to examine patterns and trends in Academia Sinica’s scholarly publications, aiming to offer insights into both the quantity and quality of its research output. Initial findings reveal trends such as saturation in paper counts, increase in citation counts, diversification of journals, shifts in prominent research areas, widening disciplinary variances, and an evolving landscape of collaborations. Although the study does not differentiate among Academia Sinica’s three divisions, specific results related to the Institute of Physics will be addressed. Additionally, comparisons with other research institutes will be explored.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 631-641"},"PeriodicalIF":4.6,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417955","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}
Pub Date : 2024-09-30DOI: 10.1016/j.cjph.2024.09.044
Li Ye, Yongchao Liang
The two-dimensional (2D) material WSe2 is frequently employed in gas sensors due to its excellent electrical properties. However, the weak interaction between the pristine WSe2 and gas molecules limits its application. Therefore, in this paper, the adsorption behavior of transition metal X (X = Fe, Mo) atom-doped monolayers WSe2 on H and O atoms and molecules of NO2, HCN, and CO gases is investigated to gain insights into the physical mechanisms of adsorbent-substrate interactions. Doping significantly improves the adsorption properties between the substrate and the gas molecules, with the best adsorption showing for NO2 gas molecules and O atoms. The relationship between transition metals and the improvement of adsorption performance is explored by the center position of transition metal d orbitals in different systems, and it is found that the higher the center position of the transition metal d band, the stronger the adsorption between adsorbent and substrate. Compared to pristine WSe2, Mo atom doping in the transition metal doped system has higher adsorption sensitivity to gas molecules and exhibits highly selective adsorption and chemisorption behaviors through high adsorption energies and electron transfer to NO2 molecules. It is demonstrated that X (X = Fe, Mo) doped WSe2 can be used as a gas-sensitive material for efficient gas detection.
二维（2D）材料 WSe2 因其出色的电学特性而经常被用于气体传感器。然而，原始 WSe2 与气体分子之间的微弱相互作用限制了它的应用。因此，本文研究了掺杂过渡金属 X（X = Fe、Mo）原子的单层 WSe2 对 H 原子、O 原子以及 NO2、HCN 和 CO 气体分子的吸附行为，以深入了解吸附剂与基底相互作用的物理机制。掺杂明显改善了基底与气体分子之间的吸附特性，其中对 NO2 气体分子和 O 原子的吸附效果最佳。通过过渡金属 d 轨道在不同体系中的中心位置探讨了过渡金属与吸附性能改善之间的关系，发现过渡金属 d 带的中心位置越高，吸附剂与基底之间的吸附越强。与原始 WSe2 相比，过渡金属掺杂体系中掺杂的 Mo 原子对气体分子具有更高的吸附灵敏度，并通过高吸附能和对 NO2 分子的电子转移表现出高选择性的吸附和化学吸附行为。实验证明，掺杂 X（X = Fe、Mo）的 WSe2 可用作高效气体检测的气敏材料。
{"title":"Study on highly selective NO2 gas sensors based on (Fe, Mo)-doped monolayer WSe2","authors":"Li Ye, Yongchao Liang","doi":"10.1016/j.cjph.2024.09.044","DOIUrl":"10.1016/j.cjph.2024.09.044","url":null,"abstract":"<div><div>The two-dimensional (2D) material WSe<sub>2</sub> is frequently employed in gas sensors due to its excellent electrical properties. However, the weak interaction between the pristine WSe<sub>2</sub> and gas molecules limits its application. Therefore, in this paper, the adsorption behavior of transition metal X (X = Fe, Mo) atom-doped monolayers WSe<sub>2</sub> on H and O atoms and molecules of NO<sub>2</sub>, HCN, and CO gases is investigated to gain insights into the physical mechanisms of adsorbent-substrate interactions. Doping significantly improves the adsorption properties between the substrate and the gas molecules, with the best adsorption showing for NO<sub>2</sub> gas molecules and O atoms. The relationship between transition metals and the improvement of adsorption performance is explored by the center position of transition metal d orbitals in different systems, and it is found that the higher the center position of the transition metal d band, the stronger the adsorption between adsorbent and substrate. Compared to pristine WSe<sub>2</sub>, Mo atom doping in the transition metal doped system has higher adsorption sensitivity to gas molecules and exhibits highly selective adsorption and chemisorption behaviors through high adsorption energies and electron transfer to NO<sub>2</sub> molecules. It is demonstrated that X (X = Fe, Mo) doped WSe<sub>2</sub> can be used as a gas-sensitive material for efficient gas detection.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 593-606"},"PeriodicalIF":4.6,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417823","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}
Pub Date : 2024-09-30DOI: 10.1016/j.cjph.2024.09.041
D. Fouejio, P. Noudem, S.S. Zekeng
Monte Carlo methods in the presence and absence of an external magnetic field were used to investigate the thermodynamic and magnetic properties of the mixed spins (3/2, 3) Ising ferrimagnets in a 2D triangular lattice consisting of sublattices A, B, and C. Two types of mixing were considered: (Model I) and (Model II). In contrast to bipartite lattices, the antiferromagnetic coupling between spin-3/2 and spin-3 in the triangular lattice leads to geometric frustrations that impact magnetic properties. Determination of ground state phase diagrams, combined with verification of whether or not there was magnetic hysteresis when crossing each transition line, revealed first- and second-order phase transition lines, as well as multicritical points. The temperature investigation in the absence of an external magnetic field revealed rich magnetic properties such as 1st- and 2nd-order phase transitions, N- and L-type compensation points, tricritical points, and critical endpoints, as well as M-, P-, Q-, R- and S-type total magnetization behaviours. The effect of the crystal field on finite-temperature phase diagrams and compensation behaviour was also carried out. As a result, the critical temperatures of Model II become constant when the crystal field is sufficiently strong. In contrast, several critical values of the crystal field for which the critical temperature is zero were identified for Model I. In the presence of a magnetic field, hysteresis behaviour and associated magnetic properties such as coercivity and magnetic remanence were investigated. The effect of crystal field and temperature was explored. Hysteresis of one to four loops were found at low temperatures when the crystal field varied. Finally, as the temperature rises, the hysteresis loops' area decreases to zero at high temperatures.
我们使用蒙特卡洛方法，在存在和不存在外部磁场的情况下，研究了由子晶格 A、B 和 C 组成的二维三角形晶格中混合自旋 (3/2, 3) 伊辛铁氧体的热力学和磁学特性：S→=（SA,SB,SC）=（3/2,3,3）（模型 I）和 S→=（SA,SB,SC）=（3/2,3,3/2）（模型 II）。与二方晶格相比，三角形晶格中自旋-3/2 和自旋-3 之间的反铁磁耦合会导致几何挫折，从而影响磁性能。在确定基态相图的同时，还验证了在跨越每条过渡线时是否存在磁滞现象，发现了一阶和二阶相变线以及多临界点。在没有外磁场的情况下进行的温度研究揭示了丰富的磁特性，如一阶和二阶相变、N 型和 L 型补偿点、三临界点和临界端点，以及 M 型、P 型、Q 型、R 型和 S 型全磁化行为。此外，还研究了晶体场对有限温度相图和补偿行为的影响。结果发现，当晶体场足够强时，模型 II 的临界温度变得恒定。与此相反，对模型 I 确定了临界温度为零的几个晶体场临界值。在磁场存在的情况下，研究了磁滞行为和相关磁特性，如矫顽力和磁剩磁。还探讨了晶体场和温度的影响。在低温条件下，当晶体磁场变化时，会出现一至四个磁环的磁滞现象。最后，随着温度的升高，磁滞环的面积在高温下减小到零。
{"title":"Magnetic and thermodynamic properties of mixed spin-3/2 and spin-3 Ising ferrimagnets on a 2D triangular lattice: Monte Carlo study","authors":"D. Fouejio, P. Noudem, S.S. Zekeng","doi":"10.1016/j.cjph.2024.09.041","DOIUrl":"10.1016/j.cjph.2024.09.041","url":null,"abstract":"<div><div>Monte Carlo methods in the presence and absence of an external magnetic field were used to investigate the thermodynamic and magnetic properties of the mixed spins (3/2, 3) Ising ferrimagnets in a 2D triangular lattice consisting of sublattices A, B, and C. Two types of mixing were considered: <span><math><mrow><mover><mi>S</mi><mo>→</mo></mover><mo>=</mo><mrow><mo>(</mo><mrow><msub><mi>S</mi><mi>A</mi></msub><mo>,</mo><mspace></mspace><msub><mi>S</mi><mi>B</mi></msub><mo>,</mo><mspace></mspace><msub><mi>S</mi><mi>C</mi></msub></mrow><mo>)</mo></mrow><mo>=</mo><mrow><mo>(</mo><mrow><mn>3</mn><mo>/</mo><mn>2</mn><mo>,</mo><mspace></mspace><mn>3</mn><mo>,</mo><mspace></mspace><mn>3</mn></mrow><mo>)</mo></mrow></mrow></math></span> (Model I) and <span><math><mrow><mover><mi>S</mi><mo>→</mo></mover><mo>=</mo><mrow><mo>(</mo><mrow><msub><mi>S</mi><mi>A</mi></msub><mo>,</mo><mspace></mspace><msub><mi>S</mi><mi>B</mi></msub><mo>,</mo><mspace></mspace><msub><mi>S</mi><mi>C</mi></msub></mrow><mo>)</mo></mrow><mo>=</mo><mrow><mo>(</mo><mrow><mn>3</mn><mo>/</mo><mn>2</mn><mo>,</mo><mspace></mspace><mn>3</mn><mo>,</mo><mspace></mspace><mn>3</mn><mo>/</mo><mn>2</mn></mrow><mo>)</mo></mrow></mrow></math></span> (Model II). In contrast to bipartite lattices, the antiferromagnetic coupling between spin-3/2 and spin-3 in the triangular lattice leads to geometric frustrations that impact magnetic properties. Determination of ground state phase diagrams, combined with verification of whether or not there was magnetic hysteresis when crossing each transition line, revealed first- and second-order phase transition lines, as well as multicritical points. The temperature investigation in the absence of an external magnetic field revealed rich magnetic properties such as 1st- and 2nd-order phase transitions, N- and L-type compensation points, tricritical points, and critical endpoints, as well as M-, P-, Q-, R- and S-type total magnetization behaviours. The effect of the crystal field on finite-temperature phase diagrams and compensation behaviour was also carried out. As a result, the critical temperatures of Model II become constant when the crystal field is sufficiently strong. In contrast, several critical values of the crystal field for which the critical temperature is zero were identified for Model I. In the presence of a magnetic field, hysteresis behaviour and associated magnetic properties such as coercivity and magnetic remanence were investigated. The effect of crystal field and temperature was explored. Hysteresis of one to four loops were found at low temperatures when the crystal field varied. Finally, as the temperature rises, the hysteresis loops' area decreases to zero at high temperatures.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 857-876"},"PeriodicalIF":4.6,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142526150","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}
Pub Date : 2024-09-28DOI: 10.1016/j.cjph.2024.09.034
Waqar Khan Usafzai , Emad H. Aly , Ioan Pop
Dual and triple solutions induced by a flexible planar surface for a micropolar two-phase fluid model are studied. The two-phase behavior in the micropolar fluid model occurs due to phase transitions between the fluid phases, influenced by interfacial stresses and heat transfer. The physical implications of these transitions are significant in understanding flow behavior under different mechanical and thermal conditions. This study examines the critical parameters and conditions that lead to these phase transitions, resulting in dual or triple solutions in the flow dynamics. The flow and thermal fields are exact solutions of the steady, two-dimensional two-phase micropolar fluid equations in the form of similarity solution. It is shown that dual and triple exact solutions exist for a highly nonlinear system. Triple solutions exist for the skin friction and temperature gradient identified by the critical numbers and It is noted that for sufficiently small values of stretching strength parameter the dual branches for two of the triple solutions exist only in the regions and where and Numerical results are also provided, validating the model and offering insights into its accuracy and behavior of the model.
研究了微波两相流体模型的柔性平面所诱发的双解和三解。受界面应力和热传导的影响，流体相之间会发生相变，从而导致微极性流体模型中的两相行为。这些转变的物理意义对于理解不同机械和热条件下的流动行为非常重要。本研究探讨了导致这些相变的关键参数和条件，这些参数和条件导致了流动动力学中的双重或三重解。流场和热场是稳定的二维两相微极流体方程以相似解形式的精确解。研究表明，高度非线性系统存在二重和三重精确解。对于临界数 ac 和 μc 所确定的皮肤摩擦和温度梯度，存在三重解。值得注意的是，对于足够小的拉伸强度参数值，三重解中的两个二重分支只存在于μ≥μc3和μ≤μc4区域，其中μc3=-5.23和μc4=-7.72。此外，还提供了数值结果，验证了模型，并对模型的准确性和行为提出了见解。
{"title":"Nonlinear dynamics of micropolar two-phase fluids: Multiple exact solutions","authors":"Waqar Khan Usafzai , Emad H. Aly , Ioan Pop","doi":"10.1016/j.cjph.2024.09.034","DOIUrl":"10.1016/j.cjph.2024.09.034","url":null,"abstract":"<div><div>Dual and triple solutions induced by a flexible planar surface for a micropolar two-phase fluid model are studied. The two-phase behavior in the micropolar fluid model occurs due to phase transitions between the fluid phases, influenced by interfacial stresses and heat transfer. The physical implications of these transitions are significant in understanding flow behavior under different mechanical and thermal conditions. This study examines the critical parameters and conditions that lead to these phase transitions, resulting in dual or triple solutions in the flow dynamics. The flow and thermal fields are exact solutions of the steady, two-dimensional two-phase micropolar fluid equations in the form of similarity solution. It is shown that dual and triple exact solutions exist for a highly nonlinear system. Triple solutions exist for the skin friction and temperature gradient identified by the critical numbers <span><math><msub><mrow><mi>a</mi></mrow><mrow><mi>c</mi></mrow></msub></math></span> and <span><math><mrow><msub><mrow><mi>μ</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>.</mo></mrow></math></span> It is noted that for sufficiently small values of stretching strength parameter the dual branches for two of the triple solutions exist only in the regions <span><math><mrow><mi>μ</mi><mo>≥</mo><msub><mrow><mi>μ</mi></mrow><mrow><msub><mrow><mi>c</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></msub><mo>,</mo></mrow></math></span> and <span><math><mrow><mi>μ</mi><mo>≤</mo><msub><mrow><mi>μ</mi></mrow><mrow><msub><mrow><mi>c</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></msub><mo>,</mo></mrow></math></span> where <span><math><mrow><msub><mrow><mi>μ</mi></mrow><mrow><msub><mrow><mi>c</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></msub><mo>=</mo><mo>−</mo><mn>5</mn><mo>.</mo><mn>23</mn></mrow></math></span> and <span><math><mrow><msub><mrow><mi>μ</mi></mrow><mrow><msub><mrow><mi>c</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></msub><mo>=</mo><mo>−</mo><mn>7</mn><mo>.</mo><mn>72</mn><mo>.</mo></mrow></math></span> Numerical results are also provided, validating the model and offering insights into its accuracy and behavior of the model.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 607-622"},"PeriodicalIF":4.6,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417956","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}
Pub Date : 2024-09-27DOI: 10.1016/j.cjph.2024.09.035
Muhammad Idrees Afridi , M.P. Mkhatshwa , Muhammad Qasim , Ali J. Chamkha
The aim of the present study is to numerically investigate the non-similar flow and heat transfer in a dissipative Eyring–Powell fluid (EPF) over a stretching surface. A constant magnetic field is applied perpendicular to the stretched surface to explore the impact of the Lorentz force. Both viscous and magnetic dissipation are considered to comprehensively examine their effects on heat transfer. The problem in hand does not admit self-similar solutions as the non-Newtonian fluid parameter varies with the spatial variable along the stream-wise direction. Consequently, the set of nonlinear partial differential equations, modeling the flow problem is nondimensionalized primarily by employing a pseudo-similarity variable and stream-wise coordinate. The non-dimensional set of nonlinear partial differential equations is solved by a newly developed and efficient “overlapping multi-domain bivariate spectral local linearization method (OMD-BSLLM)”. The current study includes residual error analysis and convergence tests to demonstrate the accuracy of the numerical method applied to the current mathematical model. Graphs show fluid flow and heat transfer results for different flow parameters, while tables display skin friction and Nusselt number values. The results indicate that the non-Newtonian fluid parameter enhances both the velocity profile and temperature distribution. The fluid decelerates with increasing the dimensionless stream wise coordinate and Hartmann number. Viscous dissipation and dimensionless stream-wise coordinate enhances the temperature profile.
{"title":"Thermal and computational analysis of MHD dissipative flow of Eyring–Powell fluid: Non-similar approach via overlapping grid-based spectral collocation scheme","authors":"Muhammad Idrees Afridi , M.P. Mkhatshwa , Muhammad Qasim , Ali J. Chamkha","doi":"10.1016/j.cjph.2024.09.035","DOIUrl":"10.1016/j.cjph.2024.09.035","url":null,"abstract":"<div><div>The aim of the present study is to numerically investigate the non-similar flow and heat transfer in a dissipative Eyring–Powell fluid (EPF) over a stretching surface. A constant magnetic field is applied perpendicular to the stretched surface to explore the impact of the Lorentz force. Both viscous and magnetic dissipation are considered to comprehensively examine their effects on heat transfer. The problem in hand does not admit self-similar solutions as the non-Newtonian fluid parameter varies with the spatial variable along the stream-wise direction. Consequently, the set of nonlinear partial differential equations, modeling the flow problem is nondimensionalized primarily by employing a pseudo-similarity variable and stream-wise coordinate. The non-dimensional set of nonlinear partial differential equations is solved by a newly developed and efficient “overlapping multi-domain bivariate spectral local linearization method (OMD-BSLLM)”. The current study includes residual error analysis and convergence tests to demonstrate the accuracy of the numerical method applied to the current mathematical model. Graphs show fluid flow and heat transfer results for different flow parameters, while tables display skin friction and Nusselt number values. The results indicate that the non-Newtonian fluid parameter enhances both the velocity profile and temperature distribution. The fluid decelerates with increasing the dimensionless stream wise coordinate and Hartmann number. Viscous dissipation and dimensionless stream-wise coordinate enhances the temperature profile.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 1026-1042"},"PeriodicalIF":4.6,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573018","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}
Pub Date : 2024-09-26DOI: 10.1016/j.cjph.2024.09.027
M. Sharif , Malick Sallah
In this study, we utilize the minimal geometric deformation technique of gravitational decoupling to extend the regular Bardeen black hole, leading to the derivation of new black hole solutions within the framework of Rastall theory. By decoupling the field equations associated with an extended matter source into two subsystems, we address the first subsystem using the metric components of the regular Bardeen black hole. The second subsystem, incorporating the effects of the additional source, is solved through a constraint imposed by a linear equation of state. By linearly combining the solutions of these subsystems, we obtain two extended models. We then explore the distinct physical properties of these models for specific values of the Rastall and decoupling parameters. Our investigations encompass effective thermodynamic variables such as density and anisotropic pressure, asymptotic flatness, energy conditions, and thermodynamic properties including Hawking temperature, entropy, and specific heat. The results reveal that both models violate asymptotic flatness of the resulting spacetimes. The violation of energy conditions indicate the presence of exotic matter, for both models. Nonetheless, the energy density, radial pressure, as well as the Hawking temperature exhibit acceptable behavior, while the specific heat and Hessian matrix suggest thermodynamic stability.
{"title":"Minimally deformed regular Bardeen black hole solutions in Rastall theory","authors":"M. Sharif , Malick Sallah","doi":"10.1016/j.cjph.2024.09.027","DOIUrl":"10.1016/j.cjph.2024.09.027","url":null,"abstract":"<div><div>In this study, we utilize the minimal geometric deformation technique of gravitational decoupling to extend the regular Bardeen black hole, leading to the derivation of new black hole solutions within the framework of Rastall theory. By decoupling the field equations associated with an extended matter source into two subsystems, we address the first subsystem using the metric components of the regular Bardeen black hole. The second subsystem, incorporating the effects of the additional source, is solved through a constraint imposed by a linear equation of state. By linearly combining the solutions of these subsystems, we obtain two extended models. We then explore the distinct physical properties of these models for specific values of the Rastall and decoupling parameters. Our investigations encompass effective thermodynamic variables such as density and anisotropic pressure, asymptotic flatness, energy conditions, and thermodynamic properties including Hawking temperature, entropy, and specific heat. The results reveal that both models violate asymptotic flatness of the resulting spacetimes. The violation of energy conditions indicate the presence of exotic matter, for both models. Nonetheless, the energy density, radial pressure, as well as the Hawking temperature exhibit acceptable behavior, while the specific heat and Hessian matrix suggest thermodynamic stability.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 794-808"},"PeriodicalIF":4.6,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142526145","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}
Pub Date : 2024-09-25DOI: 10.1016/j.cjph.2024.09.031
Junjie Wang , Jieqiong Xu , Xiaoyi Mo , Jimin Qiu
The mean-field model is an important method for understanding the complex dynamics of the nervous system at different spatial levels and for simulating and theoretically analysing the collective dynamic behaviour of large neural populations. In the work, we construct an improved mean-field system of neural networks coupled with quadratic integrate-and-fire neurons and examine the discharge patterns for networks by analysing such a model, which is a three-dimensional smooth differential system. Bifurcation analysis of the mean-field model is conducted from both theoretical and simulation perspectives, we obtain the bifurcation conditions of some co-dimension-two bifurcations and divide the parameter space into different regimes by simulating two parameters bifurcation diagrams. We find a close correspondence, though with some variance, between the mean-field model and neural network when comparing the firing patterns of the two models in various parameter regimes. In summary, the obtained mean-field description builds the bridge between the parameters of neurons or networks and that of a mean-field system to ensure we can compare them and understand the connections between them. Specifically, the mean-field model can reflect the dynamics of neural networks from a macroscopic perspective, and its bifurcation can predict the behaviour of neural networks to a certain extent and understand the mechanisms behind them, such as bursting dynamics of neural networks.
{"title":"Predicting the firing behaviour of neural network through the bifurcation analysis of derivative mean-field model","authors":"Junjie Wang , Jieqiong Xu , Xiaoyi Mo , Jimin Qiu","doi":"10.1016/j.cjph.2024.09.031","DOIUrl":"10.1016/j.cjph.2024.09.031","url":null,"abstract":"<div><div>The mean-field model is an important method for understanding the complex dynamics of the nervous system at different spatial levels and for simulating and theoretically analysing the collective dynamic behaviour of large neural populations. In the work, we construct an improved mean-field system of neural networks coupled with quadratic integrate-and-fire neurons and examine the discharge patterns for networks by analysing such a model, which is a three-dimensional smooth differential system. Bifurcation analysis of the mean-field model is conducted from both theoretical and simulation perspectives, we obtain the bifurcation conditions of some co-dimension-two bifurcations and divide the parameter space into different regimes by simulating two parameters bifurcation diagrams. We find a close correspondence, though with some variance, between the mean-field model and neural network when comparing the firing patterns of the two models in various parameter regimes. In summary, the obtained mean-field description builds the bridge between the parameters of neurons or networks and that of a mean-field system to ensure we can compare them and understand the connections between them. Specifically, the mean-field model can reflect the dynamics of neural networks from a macroscopic perspective, and its bifurcation can predict the behaviour of neural networks to a certain extent and understand the mechanisms behind them, such as bursting dynamics of neural networks.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 779-793"},"PeriodicalIF":4.6,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142445600","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}
Pub Date : 2024-09-24DOI: 10.1016/j.cjph.2024.09.032
Mohammed Alkinidri , A. Rauf , A. Farooq , F. Mustafa , S.A. Shehzad , M.K. Siddiq
A laminar two-dimensional magnetized micropolar fluid flow passed through a stretchable surface is examined. The axi-symmetric time-independent thermal flow experienced the impacts of Darcy's law, thermal conductivity, and Newtonian heating. The dimensionalized flow model is governed by similarity transformations. The resulting non-linear flow system is numerically solved through Runge-Kutta-Fehlberg (RKF-45) built in scheme. The graphics illustration of velocity and thermal fields for multiple physical parameters is presented. The numerical values at the disk surface for couple stresses, thermal rate, and shear stresses are also calculated. A Bayesian approach is used to assess the association degree amongst the under-study constraints and variables. The magnitude of the microrotational profiles is enhanced by the combined effect of micropolar parameters while an opposite effect is observed in microrotational field against magnetic and porosity parameters. The temperature field is modified through enhancing values of conjugate parameters. Moreover, such thermal field is larger for variable thermal conductivity as assumed to constant fluid property.
{"title":"Influences of Newtonian heating and Darcy's law in micropolar fluid flow over a magnetized stretchable disk: A Bayesian analysis","authors":"Mohammed Alkinidri , A. Rauf , A. Farooq , F. Mustafa , S.A. Shehzad , M.K. Siddiq","doi":"10.1016/j.cjph.2024.09.032","DOIUrl":"10.1016/j.cjph.2024.09.032","url":null,"abstract":"<div><div>A laminar two-dimensional magnetized micropolar fluid flow passed through a stretchable surface is examined. The axi-symmetric time-independent thermal flow experienced the impacts of Darcy's law, thermal conductivity, and Newtonian heating. The dimensionalized flow model is governed by similarity transformations. The resulting non-linear flow system is numerically solved through Runge-Kutta-Fehlberg (RKF-45) built in scheme. The graphics illustration of velocity and thermal fields for multiple physical parameters is presented. The numerical values at the disk surface for couple stresses, thermal rate, and shear stresses are also calculated. A Bayesian approach is used to assess the association degree amongst the under-study constraints and variables. The magnitude of the microrotational profiles is enhanced by the combined effect of micropolar parameters while an opposite effect is observed in microrotational field against magnetic and porosity parameters. The temperature field is modified through enhancing values of conjugate parameters. Moreover, such thermal field is larger for variable thermal conductivity as assumed to constant fluid property.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 403-415"},"PeriodicalIF":4.6,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417961","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}
Pub Date : 2024-09-23DOI: 10.1016/j.cjph.2024.09.028
Muhammad Sajid , Niaz Ali Khan , Muzamil Shah
The Aubry–André model is a fundamental theoretical model that exhibits interesting topological features. In this paper, we examine topologically protected boundary states in the inhomogeneous off-diagonal Aubry–André model. In contrast to the homogeneous case, the inhomogeneity triggers boundary states at phase boundaries that separate two distinct non-trivial topological domains. Remarkably, the topological character of the boundary states is predicted through topological pumping, where a boundary state is transferred from one boundary across the bulk region to the other by adiabatically tuning the pump parameter. Moreover, the role of the off-diagonal modulation strength () on the transfer efficiency of the topological pumping is addressed. To support our results, we investigate the time evolution of a continuous-time quantum walk and show that its spread rate and are inversely related. Our work provides a new avenue to harness topological features of the Aubry–André model, where topological pumping can be used for robust quantum transport.
{"title":"Topological pumping in an inhomogeneous Aubry–André model","authors":"Muhammad Sajid , Niaz Ali Khan , Muzamil Shah","doi":"10.1016/j.cjph.2024.09.028","DOIUrl":"10.1016/j.cjph.2024.09.028","url":null,"abstract":"<div><div>The Aubry–André model is a fundamental theoretical model that exhibits interesting topological features. In this paper, we examine topologically protected boundary states in the inhomogeneous off-diagonal Aubry–André model. In contrast to the homogeneous case, the inhomogeneity triggers boundary states at phase boundaries that separate two distinct non-trivial topological domains. Remarkably, the topological character of the boundary states is predicted through topological pumping, where a boundary state is transferred from one boundary across the bulk region to the other by adiabatically tuning the pump parameter. Moreover, the role of the off-diagonal modulation strength (<span><math><mi>λ</mi></math></span>) on the transfer efficiency of the topological pumping is addressed. To support our results, we investigate the time evolution of a continuous-time quantum walk and show that its spread rate and <span><math><mi>λ</mi></math></span> are inversely related. Our work provides a new avenue to harness topological features of the Aubry–André model, where topological pumping can be used for robust quantum transport.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 311-320"},"PeriodicalIF":4.6,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358111","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}
Pub Date : 2024-09-23DOI: 10.1016/j.cjph.2024.09.026
M. Sharif, Tayyab Naseer, Areej Tabassum
In this paper, we present a novel solution representing the gravastar (or gravitational vacuum star) model within the framework of non-conservative Rastall gravity. As a viable alternative to black holes, the geometry of a gravastar comprises three distinct regions: the inner sector, the intermediate layer, and the exterior domain. Utilizing the temporal component of Tolman IV spacetime, we derive the singularity-free radial metric potentials for both the inner and intermediate regions. Further, by aligning the thin shell with the external Schwarzschild line element, we establish boundary conditions in order to determine unknown constants that appear due to the chosen ansatz and performing some integrations. Subsequently, we investigate various properties for the gravastar’s shell, including the equation of state parameter, proper length, energy, entropy and gravitational redshift for four different values of the Rastall parameter. It is concluded that the gravastar structure exists and provides a feasible substitute of black holes in the framework of Rastall theory.
{"title":"Study of gravastar admitting Tolman IV spacetime in Rastall theory","authors":"M. Sharif, Tayyab Naseer, Areej Tabassum","doi":"10.1016/j.cjph.2024.09.026","DOIUrl":"10.1016/j.cjph.2024.09.026","url":null,"abstract":"<div><div>In this paper, we present a novel solution representing the gravastar (or gravitational vacuum star) model within the framework of non-conservative Rastall gravity. As a viable alternative to black holes, the geometry of a gravastar comprises three distinct regions: the inner sector, the intermediate layer, and the exterior domain. Utilizing the temporal component of Tolman IV spacetime, we derive the singularity-free radial metric potentials for both the inner and intermediate regions. Further, by aligning the thin shell with the external Schwarzschild line element, we establish boundary conditions in order to determine unknown constants that appear due to the chosen ansatz and performing some integrations. Subsequently, we investigate various properties for the gravastar’s shell, including the equation of state parameter, proper length, energy, entropy and gravitational redshift for four different values of the Rastall parameter. It is concluded that the gravastar structure exists and provides a feasible substitute of black holes in the framework of Rastall theory.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 579-592"},"PeriodicalIF":4.6,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417943","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}
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