Pub Date : 2024-09-20DOI: 10.1016/j.cjph.2024.09.023
A.V. Nikulov
Jorge Hirsch drew attention to the contradiction of the Meissner effect with Faraday’s law and the law of angular momentum conservation. This article draws attention to the fact that the angular momentum can change without any force only due to quantization in both microscopic and macroscopic quantum phenomena. But if in the first case this change cannot exceed the Planck constant, then in the second case this change is macroscopic due to a violation of the correspondence principle. To explain the violation of the correspondence principle, Lev Landau postulated in 1941 that microscopic particles in superfluid helium and superconductor cannot move separately. Quantization can change not only the angular momentum, but also the kinetic energy of a superconducting condensate on a macroscopic amount. For this reason, the Meissner effect and other macroscopic quantum phenomena contradict the second law of thermodynamics. The reluctance of physicists to admit the violation of the second law of thermodynamics provoked a false understanding of the phenomenon of superconductivity and obvious contradictions in books on superconductivity.
{"title":"A problem with the conservation law observed in macroscopic quantum phenomena is a consequence of violation of the correspondence principle","authors":"A.V. Nikulov","doi":"10.1016/j.cjph.2024.09.023","DOIUrl":"10.1016/j.cjph.2024.09.023","url":null,"abstract":"<div><div>Jorge Hirsch drew attention to the contradiction of the Meissner effect with Faraday’s law and the law of angular momentum conservation. This article draws attention to the fact that the angular momentum can change without any force only due to quantization in both microscopic and macroscopic quantum phenomena. But if in the first case this change cannot exceed the Planck constant, then in the second case this change is macroscopic due to a violation of the correspondence principle. To explain the violation of the correspondence principle, Lev Landau postulated in 1941 that microscopic particles in superfluid helium and superconductor cannot move separately. Quantization can change not only the angular momentum, but also the kinetic energy of a superconducting condensate on a macroscopic amount. For this reason, the Meissner effect and other macroscopic quantum phenomena contradict the second law of thermodynamics. The reluctance of physicists to admit the violation of the second law of thermodynamics provoked a false understanding of the phenomenon of superconductivity and obvious contradictions in books on superconductivity.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 270-283"},"PeriodicalIF":4.6,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358113","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 : 2024-09-19DOI: 10.1016/j.cjph.2024.09.016
Anish Kumar , B.S. Bhadauria , Ismail , S.N. Rai
In this paper, the influence of three different types of gravity modulation on the stability of a layer of Oldroyd-B nanofluid in various enclosures is investigated. Gravity modulation using sine, square, and triangular waveforms can be significant. It has various applications, such as industrial processes, electronic cooling, and material science. The Oldroyd-B liquid model is significant because of its numerous applications, including the production of plastic sheets and polymer extrusion through a slit, dye in the polymer industry, biological solution of paint, tars, glues, and so on. We found the expression of the Rayleigh number by applying the normal mode technique in linear stability analysis. The results demonstrate that the porosity and porous parameters stabilize the system. The system becomes unstable due to the aspect ratio. This result implies that convection travels faster in a tall enclosure compared to a square enclosure and a shallow enclosure. In nonlinear analysis, we found the Nusselt and Sherwood numbers for heat and mass transportation. In heat and mass transfer, the Deborah number, retardation parameter, gravity modulation, porous parameter, porosity, and aspect ratio play essential roles. Porous parameter and porosity delayed the rate of heat and mass transportation. The value of the retardation parameter increases then the heat and mass transportation decreases. The system’s heat and mass transfer increases by increasing the Deborah number’s value. The aspect ratio increases the system’s heat and mass transfer. The heat and mass transfer in tall enclosure is much higher than in square and shallow enclosures.
{"title":"Thermal instability on heat and mass transfer of Oldroyd-B nanofluid with several types of gravity modulation in various enclosures","authors":"Anish Kumar , B.S. Bhadauria , Ismail , S.N. Rai","doi":"10.1016/j.cjph.2024.09.016","DOIUrl":"10.1016/j.cjph.2024.09.016","url":null,"abstract":"<div><div>In this paper, the influence of three different types of gravity modulation on the stability of a layer of Oldroyd-B nanofluid in various enclosures is investigated. Gravity modulation using sine, square, and triangular waveforms can be significant. It has various applications, such as industrial processes, electronic cooling, and material science. The Oldroyd-B liquid model is significant because of its numerous applications, including the production of plastic sheets and polymer extrusion through a slit, dye in the polymer industry, biological solution of paint, tars, glues, and so on. We found the expression of the Rayleigh number by applying the normal mode technique in linear stability analysis. The results demonstrate that the porosity and porous parameters stabilize the system. The system becomes unstable due to the aspect ratio. This result implies that convection travels faster in a tall enclosure compared to a square enclosure and a shallow enclosure. In nonlinear analysis, we found the Nusselt and Sherwood numbers for heat and mass transportation. In heat and mass transfer, the Deborah number, retardation parameter, gravity modulation, porous parameter, porosity, and aspect ratio play essential roles. Porous parameter and porosity delayed the rate of heat and mass transportation. The value of the retardation parameter increases then the heat and mass transportation decreases. The system’s heat and mass transfer increases by increasing the Deborah number’s value. The aspect ratio increases the system’s heat and mass transfer. The heat and mass transfer in tall enclosure is much higher than in square and shallow enclosures.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 565-578"},"PeriodicalIF":4.6,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417957","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 : 2024-09-19DOI: 10.1016/j.cjph.2024.09.015
Debjit Pal , Dipak Kesh , Debasis Mukherjee
In this article, we investigate temporal as well as spatiotemporal dynamics of a predator–prey system where prey grows according to Smith growth function and prey refuges in predator poisoned environment. Self as well as cross diffusion are taken into consideration to describe spatial moment of the species which make the system more realistic. This study aims to investigate the role of prey refuge, toxin-carrying carcass and the impact of cross-diffusion on the spatial distribution of species densities and associated patterns. The existence of equilibria and their stability conditions for non-spatial system are derived. We discuss the occurrence of Hopf bifurcation and detect the stability of limit cycle by computing first Lyapunov number. Temporal dynamics of the system is studied by varying the significant parameters. Study reveals that both prey refuge and fatality rate of predator due to toxin-carrying carcass, initially makes the system stable for low refuge and fatality rate but predator population goes to extinction as those effects increase. Turing instability conditions are listed and different instability regions so formed are discussed. In Turing region, pattern selection with the help of amplitude equation via weakly nonlinear analysis are performed which also numerically supported. Intensity of refuge and fatality rate due to toxin carrying carcass result paradox with real ecological world due to the presence of cross diffusion. Various kind of patterns such as mixture of stripe and spot, spot, irregular chaotic patterns emerge due to Hopf and Turing instability. Particularly, spatiotemporal chaos is a controversial topic because of its significant consequences for population dynamics. The results of this work are expected to contribute to a better understanding the level of prey refuge, use of toxin-carrying carcass considering movement in population and effect of cross-diffusion.
{"title":"Pattern dynamics in a predator–prey model with Smith growth function and prey refuge in predator poisoned environment","authors":"Debjit Pal , Dipak Kesh , Debasis Mukherjee","doi":"10.1016/j.cjph.2024.09.015","DOIUrl":"10.1016/j.cjph.2024.09.015","url":null,"abstract":"<div><div>In this article, we investigate temporal as well as spatiotemporal dynamics of a predator–prey system where prey grows according to Smith growth function and prey refuges in predator poisoned environment. Self as well as cross diffusion are taken into consideration to describe spatial moment of the species which make the system more realistic. This study aims to investigate the role of prey refuge, toxin-carrying carcass and the impact of cross-diffusion on the spatial distribution of species densities and associated patterns. The existence of equilibria and their stability conditions for non-spatial system are derived. We discuss the occurrence of Hopf bifurcation and detect the stability of limit cycle by computing first Lyapunov number. Temporal dynamics of the system is studied by varying the significant parameters. Study reveals that both prey refuge and fatality rate of predator due to toxin-carrying carcass, initially makes the system stable for low refuge and fatality rate but predator population goes to extinction as those effects increase. Turing instability conditions are listed and different instability regions so formed are discussed. In Turing region, pattern selection with the help of amplitude equation via weakly nonlinear analysis are performed which also numerically supported. Intensity of refuge and fatality rate due to toxin carrying carcass result paradox with real ecological world due to the presence of cross diffusion. Various kind of patterns such as mixture of stripe and spot, spot, irregular chaotic patterns emerge due to Hopf and Turing instability. Particularly, spatiotemporal chaos is a controversial topic because of its significant consequences for population dynamics. The results of this work are expected to contribute to a better understanding the level of prey refuge, use of toxin-carrying carcass considering movement in population and effect of cross-diffusion.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 366-386"},"PeriodicalIF":4.6,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417960","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 : 2024-09-19DOI: 10.1016/j.cjph.2024.09.025
Peihong Li , Zhiqiang Liao , Hitoshi Tabata
Logical stochastic resonance (LSR) systems are physical nonlinear systems capable of robust Boolean logic operations under the influence of noise. While LSR systems suitable for electronic circuit implementation have been extensively studied, research on condensed matter LSR systems remains limited to constrained bistability with saturation characteristic. Considering the presence of periodic nonlinearities in many physical systems, a deformable sine-Gordon-shaped Remoissenet–Peyrard potential (RPP)-based LSR system is proposed for the first time in this work. Testing under both noise-free and noisy conditions proves the existence of parameter-induced LSR phenomena in the proposed system. Moreover, we find that a relatively wide potential well shape contributes to enhanced noise robustness in the RPP-based LSR system. Additionally, traditional polynomial nonlinearity-based LSR systems are compared with the proposed system. Regardless of whether the noise is Gaussian white noise or composite noise containing spiking pulses, the RPP-based LSR system exhibits superior robustness. The results demonstrate the exceptional advantages of the RPP-based LSR system and encourage further design of condensed matter LSR systems based on deformable periodic nonlinearities.
{"title":"Parameter-induced logical stochastic resonance in substrate potential with deformable sine-Gordon shape","authors":"Peihong Li , Zhiqiang Liao , Hitoshi Tabata","doi":"10.1016/j.cjph.2024.09.025","DOIUrl":"10.1016/j.cjph.2024.09.025","url":null,"abstract":"<div><div>Logical stochastic resonance (LSR) systems are physical nonlinear systems capable of robust Boolean logic operations under the influence of noise. While LSR systems suitable for electronic circuit implementation have been extensively studied, research on condensed matter LSR systems remains limited to constrained bistability with saturation characteristic. Considering the presence of periodic nonlinearities in many physical systems, a deformable sine-Gordon-shaped Remoissenet–Peyrard potential (RPP)-based LSR system is proposed for the first time in this work. Testing under both noise-free and noisy conditions proves the existence of parameter-induced LSR phenomena in the proposed system. Moreover, we find that a relatively wide potential well shape contributes to enhanced noise robustness in the RPP-based LSR system. Additionally, traditional polynomial nonlinearity-based LSR systems are compared with the proposed system. Regardless of whether the noise is Gaussian white noise or composite noise containing spiking pulses, the RPP-based LSR system exhibits superior robustness. The results demonstrate the exceptional advantages of the RPP-based LSR system and encourage further design of condensed matter LSR systems based on deformable periodic nonlinearities.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 542-553"},"PeriodicalIF":4.6,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-18DOI: 10.1016/j.cjph.2024.09.007
Tianwei Zhang , Yongyan Yang , Sufang Han
The article proposes a new approach to synchronizing space–time discrete stochastic neural networks with random switching delays. This is achieved by employing a control in the boundary, which is based on node-to-node clustering and controlling theories. The design of the control in the boundary for synchronizing space–time discrete stochastic neural networks in the form of clusters is based on the establishment of several significant sequential inequalities and the creation of cluster information. Also, an executable computer algorithm has been developed to streamline the implementation of the findings presented in this paper. The current study represents a pioneering approach in considering spatial discrete factors, providing a solid foundation for future research and offering theoretical and practical guidance.
{"title":"Node-to-node clustering asymptotic synchronized discrete stochastic neural networks in time and space with Bernoulli switching delay","authors":"Tianwei Zhang , Yongyan Yang , Sufang Han","doi":"10.1016/j.cjph.2024.09.007","DOIUrl":"10.1016/j.cjph.2024.09.007","url":null,"abstract":"<div><div>The article proposes a new approach to synchronizing space–time discrete stochastic neural networks with random switching delays. This is achieved by employing a control in the boundary, which is based on node-to-node clustering and controlling theories. The design of the control in the boundary for synchronizing space–time discrete stochastic neural networks in the form of clusters is based on the establishment of several significant sequential inequalities and the creation of cluster information. Also, an executable computer algorithm has been developed to streamline the implementation of the findings presented in this paper. The current study represents a pioneering approach in considering spatial discrete factors, providing a solid foundation for future research and offering theoretical and practical guidance.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 743-754"},"PeriodicalIF":4.6,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441477","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 : 2024-09-17DOI: 10.1016/j.cjph.2024.09.014
M. Sharif, Iqra Ibrar
This manuscript aims to study the viability and stability of a pulsar SAX J1748.9-2021, containing a charged anisotropic matter configuration within the framework of theory ( and are the non-metricity scalar and energy–momentum tensor, respectively). We employ a non-singular solution and a specific model of this gravitational theory and use junction conditions to determine the unknown constants in the metric coefficients. We explore different geometric and physical properties using astrophysical observations from the pulsar SAX J1748.9-2021, which is found in X-ray binary systems within globular clusters. This framework establishes relationships between various physical quantities, including fluid parameters, anisotropy, mass–radius relation, redshift, the Zeldovich condition, energy conditions, causality conditions, adiabatic index, Tolman–Oppenheimer–Volkoff equation, equation of state parameter and compactness. Our findings affirm the feasibility and stability of the proposed charged pulsar within this theoretical framework.
本手稿旨在研究脉冲星 SAX J1748.9-2021 的可行性和稳定性，该脉冲星在 f(Q,T) 理论（Q 和 T 分别为非度量标量和能动张量）框架内包含一个带电的各向异性物质构型。我们采用了该引力理论的非矢量解和特定模型，并利用结点条件确定了度量系数中的未知常数。我们利用对脉冲星 SAX J1748.9-2021 的天体物理观测结果来探索不同的几何和物理特性，该脉冲星存在于球状星团内的 X 射线双星系统中。这一框架建立了各种物理量之间的关系，包括流体参数、各向异性、质量半径关系、红移、泽尔多维奇条件、能量条件、因果关系条件、绝热指数、托尔曼-奥本海默-沃尔科夫方程、状态方程参数和紧凑性。我们的研究结果肯定了在这一理论框架内提出的带电脉冲星的可行性和稳定性。
{"title":"Stability and viability of charged anisotropic pulsar SAX J1748.9-2021 in extended symmetric teleparallel gravity","authors":"M. Sharif, Iqra Ibrar","doi":"10.1016/j.cjph.2024.09.014","DOIUrl":"10.1016/j.cjph.2024.09.014","url":null,"abstract":"<div><div>This manuscript aims to study the viability and stability of a pulsar SAX J1748.9-2021, containing a charged anisotropic matter configuration within the framework of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>Q</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span> theory (<span><math><mi>Q</mi></math></span> and <span><math><mi>T</mi></math></span> are the non-metricity scalar and energy–momentum tensor, respectively). We employ a non-singular solution and a specific model of this gravitational theory and use junction conditions to determine the unknown constants in the metric coefficients. We explore different geometric and physical properties using astrophysical observations from the pulsar SAX J1748.9-2021, which is found in X-ray binary systems within globular clusters. This framework establishes relationships between various physical quantities, including fluid parameters, anisotropy, mass–radius relation, redshift, the Zeldovich condition, energy conditions, causality conditions, adiabatic index, Tolman–Oppenheimer–Volkoff equation, equation of state parameter and compactness. Our findings affirm the feasibility and stability of the proposed charged pulsar within this theoretical framework.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 333-352"},"PeriodicalIF":4.6,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417944","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 : 2024-09-16DOI: 10.1016/j.cjph.2024.09.019
Ika Novitasari , San-Liang Lee
The technology for heterogeneously integrating active III-V material structures on silicon photonic platforms has gained considerable advancement in recent years. Most of the prior work utilizes the silicon-on-insulator (SOI) platform with a thicker waveguide than the popular 220 nm thick silicon layer to achieve high coupling between the III-V waveguide and SOI waveguide. The thicker SOI waveguide results in closer effective refractive indices between the two heterogeneous waveguide structures to achieve better resonance conditions. Here, we demonstrate excellent light coupling from an active III-V structure to an SOI waveguide with a standard 220 nm Si waveguide by incorporating the grating-assisted co-directional coupler (GACC) method. The GACC grating structure can be formed on either side of the III-V and Si wafers. With the GACC scheme, a thicker adhesive for bonding the two different materials can be used. The simulation verifies that over 94 % energy coupling efficiency can be obtained by using a 100 nm thick DVS-BCB as the bonding layer. High coupling performance can be maintained over a 40 nm wavelength range around 1550 nm. The high coupling efficiency can be achieved with good phase matching and mode matching between the super-modes of the hybrid structure.
{"title":"High optical coupling between hybrid III-V and SOI platform with grating-assisted co-directional couplers","authors":"Ika Novitasari , San-Liang Lee","doi":"10.1016/j.cjph.2024.09.019","DOIUrl":"10.1016/j.cjph.2024.09.019","url":null,"abstract":"<div><div>The technology for heterogeneously integrating active III-V material structures on silicon photonic platforms has gained considerable advancement in recent years. Most of the prior work utilizes the silicon-on-insulator (SOI) platform with a thicker waveguide than the popular 220 nm thick silicon layer to achieve high coupling between the III-V waveguide and SOI waveguide. The thicker SOI waveguide results in closer effective refractive indices between the two heterogeneous waveguide structures to achieve better resonance conditions. Here, we demonstrate excellent light coupling from an active III-V structure to an SOI waveguide with a standard 220 nm Si waveguide by incorporating the grating-assisted co-directional coupler (GACC) method. The GACC grating structure can be formed on either side of the III-V and Si wafers. With the GACC scheme, a thicker adhesive for bonding the two different materials can be used. The simulation verifies that over 94 % energy coupling efficiency can be obtained by using a 100 nm thick DVS-BCB as the bonding layer. High coupling performance can be maintained over a 40 nm wavelength range around 1550 nm. The high coupling efficiency can be achieved with good phase matching and mode matching between the super-modes of the hybrid structure.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 688-700"},"PeriodicalIF":4.6,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-15DOI: 10.1016/j.cjph.2024.09.020
Hui-Chi Lin , Wei-Hao Chou , Yu-Sung Liu
In this study, we demonstrate an all-range multistable liquid crystal (LC) wave plate. Its multistability arises from the formation of silica nanoparticle networks within the LC cell on the substrates, which stabilize LC molecules and induce varying phase retardation. Modulating the phase retardation of the LC wave plate can be achieved through the application of a DC pulse or by adjusting the frequency of the pulse. This multistable characteristic not only conserves energy but also enhances its versatility across diverse domains.
{"title":"Frequency and voltage-modulation multistable wave plate based on liquid crystals doped with silica nanoparticles","authors":"Hui-Chi Lin , Wei-Hao Chou , Yu-Sung Liu","doi":"10.1016/j.cjph.2024.09.020","DOIUrl":"10.1016/j.cjph.2024.09.020","url":null,"abstract":"<div><div>In this study, we demonstrate an all-range multistable liquid crystal (LC) wave plate. Its multistability arises from the formation of silica nanoparticle networks within the LC cell on the substrates, which stabilize LC molecules and induce varying phase retardation. Modulating the phase retardation of the LC wave plate can be achieved through the application of a DC pulse or by adjusting the frequency of the pulse. This multistable characteristic not only conserves energy but also enhances its versatility across diverse domains.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 642-650"},"PeriodicalIF":4.6,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417822","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 : 2024-09-15DOI: 10.1016/j.cjph.2024.09.021
Huaijin Ma , Lei Gao , Xiang Jin , Jing Zhao , Jianjun Zhao , Jiaohong Huang
This paper focuses on the magnetocaloric effect (MCE) of Gd20Tb20Er20Al20M20 (M = Fe, Co) high-entropy metallic glasses (HE-MGs). XRD and TEM results indicate that both HE-MGs are amorphous. Magnetic studies show that both HE-MGs display spin-glass behavior, undergo a second-order phase transition from ferromagnetic to paramagnetic, and exhibit soft magnetic properties at the Curie temperature (TC). Notable large and broad table-like magnetic entropy change characteristics of Gd20Tb20Er20Al20Fe20 (Gd20Tb20Er20Al20Co20) appear near a TC of 92 (51) K. Hence, under 7 T magnetic field, |-∆SMmax|, ∆ TFWHM, and RCP are 7.83 (10.10) J·kg-1·K-1, 120.07 (71.88) K, and 1008.26 (805.70) J·kg-1, respectively. Furthermore, the modulation of the magnetic and magnetocaloric properties of the samples after substitution of Fe for Co was revealed by the intricate 3d-3d and 3d-4f exchange interactions within the system. The magnetic phase transition critical behaviors in both HE-MGs were analyzed using the scaling law to clarify the deviation of amorphous materials from the mean-field theory. Thus, this study not only highlights the potential of this material for low-temperature magnetic refrigeration applications, but also expands our understanding of its physical properties.
{"title":"Low-temperature magnetic refrigeration in Gd20Tb20Er20Al20M20 (M = Fe, Co) high-entropy metallic glasses","authors":"Huaijin Ma , Lei Gao , Xiang Jin , Jing Zhao , Jianjun Zhao , Jiaohong Huang","doi":"10.1016/j.cjph.2024.09.021","DOIUrl":"10.1016/j.cjph.2024.09.021","url":null,"abstract":"<div><div>This paper focuses on the magnetocaloric effect (MCE) of Gd<sub>20</sub>Tb<sub>20</sub>Er<sub>20</sub>Al<sub>20</sub>M<sub>20</sub> (M = Fe, Co) high-entropy metallic glasses (HE-MGs). XRD and TEM results indicate that both HE-MGs are amorphous. Magnetic studies show that both HE-MGs display spin-glass behavior, undergo a second-order phase transition from ferromagnetic to paramagnetic, and exhibit soft magnetic properties at the Curie temperature (<em>T</em><sub>C</sub>). Notable large and broad table-like magnetic entropy change characteristics of Gd<sub>20</sub>Tb<sub>20</sub>Er<sub>20</sub>Al<sub>20</sub>Fe<sub>20</sub> (Gd<sub>20</sub>Tb<sub>20</sub>Er<sub>20</sub>Al<sub>20</sub>Co<sub>20</sub>) appear near a <em>T</em><sub>C</sub> of 92 (51) K. Hence, under 7 T magnetic field, |-∆<em>S</em><sub>M</sub><sup>max</sup>|, ∆ <em>T</em><sub>FWHM</sub>, and <em>RCP</em> are 7.83 (10.10) J·kg<sup>-1</sup>·K<sup>-1</sup>, 120.07 (71.88) K, and 1008.26 (805.70) J·kg<sup>-1</sup>, respectively. Furthermore, the modulation of the magnetic and magnetocaloric properties of the samples after substitution of Fe for Co was revealed by the intricate 3d-3d and 3d-4f exchange interactions within the system. The magnetic phase transition critical behaviors in both HE-MGs were analyzed using the scaling law to clarify the deviation of amorphous materials from the mean-field theory. Thus, this study not only highlights the potential of this material for low-temperature magnetic refrigeration applications, but also expands our understanding of its physical properties.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"92 ","pages":"Pages 353-365"},"PeriodicalIF":4.6,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417819","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 : 2024-09-14DOI: 10.1016/j.cjph.2024.09.018
Mritunjoy Das, Pralay Kumar Karmakar
The nonlinear Jeans instability dynamics in viscoelastic astrofluids within the Eddington-inspired Born-Infeld (EiBI) gravitational framework excitable in star-forming interstellar cloud fluids is semi-analytically investigated. Application of multiple scaling techniques here results in a unique form of the Korteweg-de Vries (KdV) equation moderated with a peculiar set of distinctive fluid polyparametric coefficients. A numerical illustrative platform portrays the excitation of diversified compressive solitary-chain wave patterns. The evolutionary existence of such structural patterns is further confirmed geometrically with the help of illustrative phase-plane analyses. The various parametric stabilizers and destabilizers, alongside accelerating and decelerating factors on the clouds, are illustratively analysed. It is seen that the composite cloud stability is significantly influenced by the strength polarity of the gravitational EiBI-parameter . The dependency of the obtained solitary wave patterns on the EiBI-polarity is further confirmed in a numerical simulation platform illustratively. Our analysis also highlights that the influence of material density on the system stability is dependent on the EiBI-polarity. The nonlinear spatiotemporal evolution of the instability reveals a unique type of soliton fission phenomenon, indicative of inherently produced additional disturbances within the astrofluid. Our obtained results could be widely helpful in application to the EiBI-centric diverse astrocosmic phenomena, such as bounded structure formation and evolution in diverse complex astroenvirons.
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