Chinese Journal of Physics最新文献

{"title":"The electrokinetic energy conversion and streaming potential analytical solutions of couple stress nanofluids in the circular polyelectrolyte-grafted nanochannel","authors":"Yue Zhang ,&nbsp;Guangpu Zhao ,&nbsp;Bo Xue ,&nbsp;Mandula Buren ,&nbsp;Yongjun Jian","doi":"10.1016/j.cjph.2024.08.021","DOIUrl":"10.1016/j.cjph.2024.08.021","url":null,"abstract":"<div><p>The purpose of this study is to investigate the variation of streaming potential and EKEC efficiency of nanofluids with couple stress in the circular polyelectrolyte-grafted (PE-grafted) nanochannel under the combined effect of periodic pressure and magnetic field. The analytical solutions of the velocity field in the PEL region and electrolyte solution are obtained by solving the modified Navier-Stokes equation and the influence of several dimensionless parameters on the streaming potential and electrokinetic energy conversion (EKEC) efficiency are further discussed graphically. The results indicate that the streaming potential decreases with increasing Hartmann number and nanoparticle diameter within a certain parameter range. The dimensionless velocity shows an oscillating trend at different oscillating Reynolds numbers, and the oscillation is more pronounced at the interface between the PEL and the electrolyte solution. In addition, the EKEC efficiency of nanofluids in soft nanochannel is compared with that in a rigid one. It is shown that the EKEC efficiency is higher in PE-grafted nanochannel, and the couple stress plays an important role in improving the EKEC efficiency. We anticipate that these findings will help to reveal a novel understanding of energy conversion in the circular PE-grafted nanochannel.</p></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142097334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Germanium metasurface near-infrared high-q absorber with symmetry-protected bound states in the continuum","authors":"Ming-Jyun Ye ,&nbsp;Rashid G. Bikbaev ,&nbsp;Dmitrii N. Maksimov ,&nbsp;Pavel S. Pankin ,&nbsp;Munho Kim ,&nbsp;Ivan V. Timofeev ,&nbsp;Kuo-Ping Chen","doi":"10.1016/j.cjph.2024.08.018","DOIUrl":"10.1016/j.cjph.2024.08.018","url":null,"abstract":"<div><p>The all-dielectric germanium nanohole (GNH) metasurface with a sub-wavelength thickness supports simultaneous excitation of quasi bound state in the continuum (BIC) and super radiant mode. By selecting the different hole depths in a germanium slab, we present a trade-off metasurface between high Q-factor and high absorption in the photonic system. The presented device demonstrated absorption of super-radiant mode ∼98.5% and quasi-BIC ∼93% without back-metal reflector at the telecommunication wavelength. The numerical results, obtained by the finite difference time domain (FDTD) method are explained in the framework of temporal coupled mode theory (TCMT).</p></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142241513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How lights affect the circadian rhythm in sleep-awake circle","authors":"Xiaodi Li,&nbsp;Ying Xu","doi":"10.1016/j.cjph.2024.08.016","DOIUrl":"10.1016/j.cjph.2024.08.016","url":null,"abstract":"<div><p>Biological neurons receive a variety of external physical stimuli that are encoded in the nervous system to regulate the circadian rhythm in animals. Most types of nonlinear circuits are effective for exploring the dynamics and biophysical properties in biological neurons by analyzing the sampled time series for output voltage. To explore the impact of light on the homeostatic regulation of sleep-wake cycle, this paper proposes an enhanced neuron model that incorporates photocurrent activation, aiming to study the fundamental principles governing the sleep-wake cycle. In this paper, the frequency and intensity of external illumination are carefully adjusted to explore the occurrence of the firing modes in this light-sensitive neuron. The numerical results suggest that the circadian rhythm system can be impaired by continuous exposure to strong and high-frequency light. Additionally, an appropriate fine-tuning of the coupling strength between neurons can further optimize the response of a neural network to external light signals. These results provide insights into the regulation of light on circadian rhythm, and thus appropriate electromagnetic radiation can be applied to prevent and treat the sleep disorders.</p></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142088800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of (r,q) distribution on ion acoustic solitary waves in a magneto-rotating plasma with application to Saturn’s magnetosphere","authors":"Dong-Ning Gao","doi":"10.1016/j.cjph.2024.07.021","DOIUrl":"10.1016/j.cjph.2024.07.021","url":null,"abstract":"<div><p>Ion acoustic waves (IAWs) are theoretically researched in a magneto-rotating plasma with cold ion fluid and <span><math><mrow><mo>(</mo><mi>r</mi><mo>,</mo><mi>q</mi><mo>)</mo></mrow></math></span> distributed electrons. The reductive perturbation method (RPM) is used to simplify fluid plasma equations, the relevant ZK and mZK equations and their solitary solutions are given. Small-k expansion method is applied to obtain the instability growth rates of ZK and mZK IAWs. The flatness and tail parameters modify the amplitude, width, soliton energy and instability growth rate for both ZK and mZK IAWs. There only exist negative ZK IAWs and positive mZK IAWs. It is noted that the increscent flatness and tail parameters result in the increasing amplitude, width, soliton energy and growth rate of ZK and mZK IAWs. These results will be helpful in understanding the plasma dynamics for a magneto-rotating plasma system containing <span><math><mrow><mo>(</mo><mi>r</mi><mo>,</mo><mi>q</mi><mo>)</mo></mrow></math></span> distributed electrons in Saturn’s magnetosphere.</p></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142048957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Crow-Kimura evolution model in case of asymmetric mutation and recombination","authors":"Vladimir Suvorov ,&nbsp;Hirobumi Mineo ,&nbsp;David B. Saakian","doi":"10.1016/j.cjph.2024.08.015","DOIUrl":"10.1016/j.cjph.2024.08.015","url":null,"abstract":"<div><p>The mutation and recombination often have different rates for forward and backward processes and this study explores the less common case of asymmetric mutation and recombination rates. The primary focus is on analyzing the error threshold transition in the context of asymmetric mutations. We investigate how the error threshold changes in the case of a single peak fitness landscape. We analyze how surplus (the availability of beneficial mutations) changes with the degree of asymmetry in mutation and recombination rates. The model is extended to include asymmetric recombination (horizontal gene transfer). We focus on the complex interplay between mutation and recombination rates in asymmetric scenarios and their effects on error thresholds, surplus, mean fitness, and other key aspects of evolutionary dynamics. The findings contribute to a more nuanced understanding of evolution in situations where biological processes do not follow the simplifying assumption of symmetric rates.</p></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142088801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative study for heat transfer characteristics of many graphene hybrid nanofluids flow over a shrinking sheet","authors":"Amr M. Mahros ,&nbsp;Emad H. Aly","doi":"10.1016/j.cjph.2024.08.010","DOIUrl":"10.1016/j.cjph.2024.08.010","url":null,"abstract":"<div><div>In this work, steady two-dimensional boundary layer flow of an electrically conductive hybrid nanofluids past a shrinking sheet, along with magnetic field, thermal radiation, suction/injection, heat source/sink and velocity slip model, has been investigated. Particularly, eight mixed hybrid graphene nanofluids of copper, silver, aluminium oxide and titanium dioxide were studied and compared with the classical graphene–water nanofluid. Appropriate similarity transformations have been used to convert the governing PDEs into a set of non-linear ODEs, then, we deduced exact solutions of the flow and temperature. In addition, possibility of obtaining no, unique and dual solutions for these functions were introduced as critical values and regions via graphs. Moreover, validation of the present solutions with those in the literature has been tabulated. Furthermore, asymptotic expression and local extremum for the most important equation were studied.</div><div>On comparing with those results in the literature at some special values of the included parameters, excellent agreements were gotten. It was mentioned that two conditions have to be simultaneously applied to result the temperature dual solution with restrictions on choosing values of specific parameters. Further, in the injection case, the temperature distributions are larger by about 66.7% on comparing with those in the suction case, for all almost the investigated parameters. To get the highest temperature, it was deduced that the copper is to be firstly added to the water and then mixed with the graphene to produce the hybrid nanofluid. Graphene–copper/water employs as a heater on increasing the Eckert number, shrinking parameter and second velocity slip (for <span><math><mrow><mi>N</mi><mo>&lt;</mo><mn>0</mn></mrow></math></span>). Furthermore, it acts as cooler with an increase of magnetic field, <span><math><mo>|</mo></math></span>heat source/sink parameter<span><math><mo>|</mo></math></span>, suction/injection parameter, solid volume fraction, first velocity slip and second velocity slip (for <span><math><mrow><mi>N</mi><mo>&gt;</mo><mn>0</mn></mrow></math></span>).</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic splitting induced ferromagnetism in chromium-doped HfSe2","authors":"Hamid Ali ,&nbsp;Obaid Iqbal ,&nbsp;Saleh S. Alarfaji ,&nbsp;Fengguang Liu ,&nbsp;Bin Hong ,&nbsp;Weisheng Zhao ,&nbsp;Dewu Yue ,&nbsp;Zahir Muhammad","doi":"10.1016/j.cjph.2024.08.013","DOIUrl":"10.1016/j.cjph.2024.08.013","url":null,"abstract":"<div><p>Two-dimensional (2D) magnetic layered materials have gained significant interest in spintronic for memory storage devices. Herein, the electronic and magnetic properties of high-quality single crystals of chromium (Cr)-doped hafnium diselenide were studied. The electronic study indicated that the Cr-doped HfSe₂ reveals the semiconducting nature with a proper bandgap as identified by angle-resolved photoemission spectroscopy and first-principle density functional theory (DFT) calculations. The magnetic results indicate that the HfSe₂ exhibited ferromagnetic characteristics with the substitution of Cr atoms in a perpendicular direction. The Cr-doped HfSe₂ sample shows a ferromagnetic phase below ∼58 K, indicating the critical temperature (<em>T</em>_c) of magnetic order, while above this temperature, it shows a paramagnetic phase that can follow the Curie-Weiss Law. It can be seen that the magnetic moment is approximately 0.16 emu/g at 5 K, which further decreases with increasing temperature until 60 K and then transforms to a paramagnetic phase. The sample can clearly show a weak out-of-plane magnetic anisotropy with a coercivity of around 50.56 Oe and a saturation magnetization value of 0.029 emu/g. Convincingly, it was observed from the ARPES results that the valence band is split due to the spin-orbit interaction of Cr atoms, which can induce ferromagnetic order. At the same time, the temperature-dependent ARPES data shows that the splitting is higher below the <em>T</em>_c, while it is weaker above the <em>T</em>_c. The DFT results revealed that near the Fermi level, the spin-up and spin-down are spin-polarized with asymmetric trends. It can be observed that substituting Cr on the octahedral sites of Hf atoms influences the electron spin order created by Hf vacancies (as validated by the magnetic coupling measured by electron paramagnetic resonance spectroscopy experiments), which can change the magnetic alignment to induce the magnetism in HfSe₂. This study highlights that doping transition metal in HfSe₂ has promising potential for future applications, especially in memory devices and spintronic technologies.</p></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142229222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on multi-resonance mechanism to achieve ultra-wideband high absorption of a metamaterial absorber in the UV to MIR range","authors":"Yanli Qu ,&nbsp;Yan Chen ,&nbsp;Shanjun Chen ,&nbsp;Qingfeng Wu ,&nbsp;Jin Liu ,&nbsp;Zao Yi ,&nbsp;Liping Fu","doi":"10.1016/j.cjph.2024.08.012","DOIUrl":"10.1016/j.cjph.2024.08.012","url":null,"abstract":"<div><p>Wideband metamaterial perfect absorbers have been extensively researched due to their excellent properties. A four-layer ultra-broadband metamaterial perfect absorber engraved with a square cavity is proposed. A clever combination of grating and square cavity allows the absorber to manifests an overall absorption of over 92 % and an average absorption rate of 97.27 % within the operational band from 280 to 5400 nm. Through analysis, it can be concluded that the coupling effects of Rayleigh anomaly (RA), magnetic resonance (MR), cavity resonance (CR), propagating surface plasmon resonance (PSPR) and local surface plasmon resonance (LSPR) result in perfect absorption. The absorber is insensitive to polarization and large angle incidence. It is worth mentioning that the average absorption rate of our structure reaches 93.32 % at a large incidence angle of 60° in TE mode, which is much higher than that of other absorbers. At 1000 K, the total photothermal conversion efficiency of our absorber is still above 90 %. The designed structure has the following advantages: high absorption, ultra-wide bandwidth, high tolerance to fabrication errors and insensitivity to large angle incidence. Thus, the absorber can be used in the solar energy harvesting and perfect stealth. Additionally, it also can be served as a reference in thermophotovoltaics, thermal imaging and infrared detection.</p></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142006387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anisotropic model of stellar objects in modified f(R) gravity","authors":"Rajesh Kumar ,&nbsp;S.K. Maurya ,&nbsp;Abdelghani Errehymy ,&nbsp;Kairat Myrzakulov ,&nbsp;Zhanbala Umbetova ,&nbsp;V.N. Pathak","doi":"10.1016/j.cjph.2024.08.011","DOIUrl":"10.1016/j.cjph.2024.08.011","url":null,"abstract":"<div><p>In this paper, we studied anisotropic models to describe compact stellar objects with a spherically symmetric matter distribution using modified <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity. To accomplish this goal, we examined two distinct models within the <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> theory of gravity. We investigated the use of the Durgapal and Fuloria analog metric potentials to construct a stellar model by solving the Einstein Field equations. Our analysis includes a discussion of the generalized Darmois-Israel junction condition, crucial for smoothly linking the interior region to the Schwarzschild exterior metric at the star’s boundary hypersurface within the framework of <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity. This junction condition requires a non-zero pressure at the boundary, which is directly related to the non-linear terms present in <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> gravity. These conditions are often overlooked by many researchers in their exploration of compact stellar models. In our study, we utilized generalized boundary conditions to determine model parameters. Furthermore, we obtained these parameters using observational data from several compact stars, including <em>4U1538-52, SAX J 1808.4-3658, EXO 1785-248, Cen X-3, 4U1820-30, PSR J1903+327, 4U1608-52</em>, and <em>PSR J1614-2230</em>. This innovative approach allowed us to conduct a comprehensive analysis of models and their physical validity. We performed various physical tests such as anisotropy, equilibrium conditions, stability, energy-density constraints, mass function, compactness, redshift, and adiabatic index to evaluate the feasibility of our models.</p></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142241965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the phase transition challenge by analyzing stability in a 5-D dynamical system linked to (2,1/2)-MSIM","authors":"Hasan Akın","doi":"10.1016/j.cjph.2024.08.008","DOIUrl":"10.1016/j.cjph.2024.08.008","url":null,"abstract":"<div><p>In this short research, we delve into the phase transition phenomenon by analyzing the stability of the dynamical system associated with the (2,1/2)-mixed spin Ising model on a Cayley tree of order three. Our analysis focuses on examining the five-dimensional dynamical system linked to the Ising model featuring mixed spin-<span><math><mrow><mo>(</mo><mn>2</mn><mo>,</mo><mn>1</mn><mo>/</mo><mn>2</mn><mo>)</mo></mrow></math></span> setups, operating within a third-order Cayley tree. By scrutinizing the Jacobian matrix of this nonlinear dynamic system, we pinpoint the repelling fixed points, corresponding to the Gibbs measures tied to the given model. The existence of these repelling fixed points enables us to predict potential phase transitions in the model by identifying any additional fixed points. We also identify the areas where the model exhibits chaotic tendencies through an examination of the Lyapunov exponent. Additionally, we seek to understand whether the order of the tree impacts the chaotic behavior observed in the dynamic system.</p></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141979708","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}