Indian Journal of Physics最新文献_第4页

Valley polarization of electrons in a graphene under modulations of the electrostatic potential barrier and the magnetic field 静电势垒和磁场调制下石墨烯中电子的谷极化

IF 2 4区物理与天体物理

Indian Journal of Physics Pub Date : 2024-08-29 DOI: 10.1007/s12648-024-03390-2

R. S. Luo, J. D. Lu, X. Y. Li, H. Wang

引用次数: 0

Lie symmetry approach for shock wave propagation in a self-gravitating non-ideal gas under the influence of monochromatic radiation and magnetic field in rotating medium 旋转介质中单色辐射和磁场影响下自重力非理想气体中冲击波传播的李对称方法

IF 2 4区物理与天体物理

Indian Journal of Physics Pub Date : 2024-08-29 DOI: 10.1007/s12648-024-03352-8

G. Nath, P. Upadhyay

{"title":"Lie symmetry approach for shock wave propagation in a self-gravitating non-ideal gas under the influence of monochromatic radiation and magnetic field in rotating medium","authors":"G. Nath, P. Upadhyay","doi":"10.1007/s12648-024-03352-8","DOIUrl":"https://doi.org/10.1007/s12648-024-03352-8","url":null,"abstract":"The propagation of cylindrical shock wave influenced by monochromatic radiation and magnetic field in a self-gravitating non-ideal gas for a rotating medium has been investigated by using the Lie symmetry method. Ahead of the shock front, the ambient density of the medium is taken as constant, while the magnetic field, azimuthal and axial velocities vary over time. By using the Lie symmetry approach, the optimal system for the governing equations, the similarity variable and transformations are obtained. By the use of derived similarity transformations, the governing equations change into a system of ODEs (ordinary differential equations). The software package “Mathematica” has been utilized to solve the system of ODEs numerically and to generate the graphs for the flow variables distribution. In this article, the strength of the shock wave and variations in the flow variables of the flow field region behind the shock front, which are influenced by the strength of the ambient magnetic field, gravitational parameter, non-idealness parameter, adiabatic exponent, and rotational parameter, are examined in detail. It has been demonstrated that the magnetic field, non-idealness parameter, adiabatic exponent, and rotational parameter have decaying effect on the shock wave. In contrast, the gravitational parameter has reversed impact on the shock strength.","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

引用次数: 0

Structural and optical properties of Cr3+ doped SiO2 nanophosphor 掺杂 Cr3+ 的二氧化硅纳米磷的结构和光学特性

IF 2 4区物理与天体物理

Indian Journal of Physics Pub Date : 2024-08-29 DOI: 10.1007/s12648-024-03392-0

L. F. Koao, R. A. Phokojoe, R. G. Moji, S. V. Motloung, T. E. Motaung, H. C. Swart

{"title":"Structural and optical properties of Cr3+ doped SiO2 nanophosphor","authors":"L. F. Koao, R. A. Phokojoe, R. G. Moji, S. V. Motloung, T. E. Motaung, H. C. Swart","doi":"10.1007/s12648-024-03392-0","DOIUrl":"https://doi.org/10.1007/s12648-024-03392-0","url":null,"abstract":"SiO2:x% Cr3+ (0 ≤ x ≤ 8) nanopowder samples were synthesized using the sol-gel method. The effect of Cr3+ doping concentration on the SiO2 nanoparticles was studied for possible application in light-emitting diodes (LEDs). Structure and optical properties of undoped and Cr3+ doped SiO2 nanoparticles were investigated in detail. X-ray diffraction (XRD) results confirmed the amorphous phase for undoped SiO2 (A-SiO2) nanopowder. However, above 0.8% Cr3+ there were secondary peaks due rhombohedral structure of chromium (III) oxide (R-Cr2O3). Ultraviolet-visible spectroscopy (UV-Vis) spectra showed a reflectance peak at around 320 nm for the undoped sample. The results showed that when the concentration of Cr3+ is increased there was an emergence of reflectance peaks at around 309, 419, and 553 nm which were attributed to the presence of the Cr2O3 lattices. The photoluminescence (PL) results revealed that with an increase in the amount of Cr3+, the maximum peaks in blue and near red emerge at around 2.82 and 1.89 eV, respectively. Those peaks may be due to defects within both SiO2 and R-Cr2O3. The emission peaks of undoped and Cr3+ doped SiO2 match well with the Uv-vis results. The international illumination colour chromaticity showed that above 0.8% Cr3+ the colour shifts from yellow to blue with an increase in Cr3+ concentration. The investigation indicated that Cr3+ doped SiO2 have a potential application in blue and yellow LED chips for lighting.","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

引用次数: 0

Study of multiple degrees of freedom entanglement in optical fiber 光纤中多自由度纠缠的研究

IF 2 4区物理与天体物理

Indian Journal of Physics Pub Date : 2024-08-28 DOI: 10.1007/s12648-024-03378-y

Huimin Zhang, Chaoying Zhao

引用次数: 0

Domain-wall dark pulse generation with polyacrylonitrile as saturable absorber 以聚丙烯腈为可饱和吸收体的域壁暗脉冲发生器

IF 2 4区物理与天体物理

Indian Journal of Physics Pub Date : 2024-08-28 DOI: 10.1007/s12648-024-03384-0

Xiaoyou Song, Abdulkadir Mukhtar Diblawe, Zian Cheak Tiu, Sameer Salam, Fatimah Ibrahim, Sulaiman Wadi Harun

引用次数: 0

Anisotropic cosmological models in f(T) theory of gravity with mixture of fluids 具有流体混合物的 f（T）引力理论中的各向异性宇宙学模型

IF 2 4区物理与天体物理

Indian Journal of Physics Pub Date : 2024-08-27 DOI: 10.1007/s12648-024-03368-0

V. J. Dagwal

引用次数: 0

A Triangular based determination of temperature using artificial intelligence 利用人工智能进行基于三角形的温度测定

IF 2 4区物理与天体物理

Indian Journal of Physics Pub Date : 2024-08-27 DOI: 10.1007/s12648-024-03381-3

Adeel Tahir, Ahmed Ali Rajput, Mustaqeem Zahid, Shafiq Ur Rehman

{"title":"A Triangular based determination of temperature using artificial intelligence","authors":"Adeel Tahir, Ahmed Ali Rajput, Mustaqeem Zahid, Shafiq Ur Rehman","doi":"10.1007/s12648-024-03381-3","DOIUrl":"https://doi.org/10.1007/s12648-024-03381-3","url":null,"abstract":"The forecasting method emerged in the middle of the twentieth century; its usage has grown exponentially in all aspects of life. More importantly, estimating modern meteorological parameters helps make good decisions regarding weather, health, and agricultural safety measures. Similarly, this study aims to find a better-fitting technique to translate Quetta’s (Pakistan) temperature distribution using its three neighboring stations, Chaman, Kalat, and Sibi. In this regard, a well-known machine learning technique named Artificial Neural Network was utilized. Additionally, four training algorithms are also considered to optimize the model performance. Apart from that, another traditional statistical model is incorporated, which is a Multiple Linear Regression (MLR). Since the temperature distribution has a nonlinear trend, MLR techniques are also useful for making predictions. Machine learning and linear statistical models are provided with seven years of data from 2011 to 2017 for training purposes. Three sets of data for 2018, 2019, and 2020 are fed to determine how these trained models show close agreements with the actual temperature distribution. Different errors are evaluated to assess model performance, such as mean squared error (MSE), mean absolute percentage error (MAPE), mean absolute bias error (MABE), and chi-squared error. ({chi }^{2}), and coefficient of determination (R2). For ANN, the models with the lowest MABE and MAPE values are ANN-RB and ANN-BR, whereas the model with the lowest MSE value, 1.3604, is the ANN-BFG model. The model with the highest correlation is the ANN-BFG model. On the other hand, MLR has an MSE of 1.4253 and a coefficient of determination of 0.9860.","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

引用次数: 0

Unveiling the physics of acoustic insulation: multilayer flow resistivity estimation 揭开隔声物理学的神秘面纱：多层流动电阻率估算

IF 2 4区物理与天体物理

Indian Journal of Physics Pub Date : 2024-08-27 DOI: 10.1007/s12648-024-03391-1

M. Sadouki

{"title":"Unveiling the physics of acoustic insulation: multilayer flow resistivity estimation","authors":"M. Sadouki","doi":"10.1007/s12648-024-03391-1","DOIUrl":"https://doi.org/10.1007/s12648-024-03391-1","url":null,"abstract":"This paper presents a computational methodology aimed at precisely estimating the physical law governing equivalent flow resistivity in multilayer rigid porous materials, with a specific focus on applications in acoustic insulation systems. While existing models are capable of predicting sound transmission through individual layers, they lack a direct theoretical analytical link between the flow resistivity of multilayer materials and the properties of their constituent layers. To address this gap, the study harnesses equivalent fluid theory, which integrates visco-inertial interactions between the material structure and the interstitial fluid. By establishing simplified expressions for the transmission coefficient of a bilayer medium under low-frequency Darcy conditions, the paper introduces a novel approach to estimation. Furthermore, it formulates a concise relationship between the resistivity of the bilayer medium and the resistivity and thickness of each layer, which extends to multilayer configurations. Experimental validation with bilayer samples demonstrates significant agreement between the directly obtained equivalent flux resistivity and the theoretically predicted values, with relative errors ranging from 3 to 18%. The significance of this paper lies in its practical implications for acoustic insulation systems, where accurate predictions of acoustic performance are crucial. The research introduces a reliable physical relationship for estimating the equivalent flow resistivity of a multilayer as a function of the flow resistivity of each constituent layer and its thickness, offering theoretical correlation with empirical data and providing an alternative to labor-intensive experimental methods and software. This contribution to acoustics facilitates accurate prediction and characterization of the acoustic properties of multilayer materials, thereby aiding in the design of effective noise control systems.","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

引用次数: 0

Effect of Sulfur dopants atoms on the electronic and optical properties of Silver oxides from hybrid density functional theory 从混合密度泛函理论看掺硫原子对银氧化物电子和光学特性的影响

IF 2 4区物理与天体物理

Indian Journal of Physics Pub Date : 2024-08-26 DOI: 10.1007/s12648-024-03366-2

W. Tebboune, H. Riane, F. Boukabrine, H. Rozale, A. Chahed, A. sayade

{"title":"Effect of Sulfur dopants atoms on the electronic and optical properties of Silver oxides from hybrid density functional theory","authors":"W. Tebboune, H. Riane, F. Boukabrine, H. Rozale, A. Chahed, A. sayade","doi":"10.1007/s12648-024-03366-2","DOIUrl":"https://doi.org/10.1007/s12648-024-03366-2","url":null,"abstract":"The structural and electronic properties, as well as the stability of Ag2O1−xSx (x = 0, 0.25, 0.5, 0.75 and 1) compounds have been investigated through first-principles calculation.The FP-LAPW method within theGGA-PBE, TB-mBJ and HSE06 functional approximations was chosen in the computational approach. The computed lattice constant for Ag2O and Ag2S was found to be consistent with the theoretical and experimental results. For electronic properties,the reproduction of the experimental band gap energy is seen with the hybrid-DFT functionalHSE06, compared to GGA-PBE and for TB-mBJ.In order to better understand the behavior of electronic states of Silver-based compounds, details of the electronic properties would be valuable. It is believed that changes of the Fermi level of a semiconductor will definitely affect its photocatalytic properties due to the contribution of strong hybridization between the O and S p states and Ag d states.From the optical results we demonstrate that the studied materials are important for optoelectronic devices because it exhibited a wide range of absorption spectra.","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

引用次数: 0

Dynamical fluctuations of pions in pp collisions at different LHC energies: an in-depth analysis with factorial correlator 不同大型强子对撞机能量下 pp 对撞中 pions 的动态波动：利用因子相关器的深入分析

IF 2 4区物理与天体物理

Indian Journal of Physics Pub Date : 2024-08-25 DOI: 10.1007/s12648-024-03385-z

Tumpa Biswas, Azharuddin Ahmed, Subhadeep Paul, Dibakar Dhar, Sanjib Kumar Manna, Mehedi Kalam, Dipak Ghosh, Prabir Kumar Haldar

{"title":"Dynamical fluctuations of pions in pp collisions at different LHC energies: an in-depth analysis with factorial correlator","authors":"Tumpa Biswas, Azharuddin Ahmed, Subhadeep Paul, Dibakar Dhar, Sanjib Kumar Manna, Mehedi Kalam, Dipak Ghosh, Prabir Kumar Haldar","doi":"10.1007/s12648-024-03385-z","DOIUrl":"https://doi.org/10.1007/s12648-024-03385-z","url":null,"abstract":"This paper presents an analysis on the basis of factorial correlators and oscillatory multiplicity moments among the pions extracted from Monte Carlo (MC) generated PYTHIA(v8.3), AMPT(v2.26) and UrQMD(v3.4) models in pp collisions at different center-of-mass (c.m) energies (sqrt{s}=) 2.76 – 13 TeV. During this investigation, we have found the presence of short-range correlation and our overall findings are accordant with the predictions of the (alpha)-model and (log)-normal approximation which indicates the existence of intermittent nature of self-similar dynamical fluctuations. Short-range Correlation strength gradually decreases with the increase in collision energies from (sqrt{s}) = (2.76-13) TeV is observed. From the analysis of oscillatory multiplicity moments, the ratios (H_q) (cumulant over factorial moments (K_q/F_q)) have been derived for each MC generated Model with LHC energies. It is extremely interesting to observe that the oscillations from PYTHIA and UrQMD are quite different from the AMPT model at (sqrt{s}) = 13 TeV.","PeriodicalId":584,"journal":{"name":"Indian Journal of Physics","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

引用次数: 0