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Performance evaluation of frequency-modulated NR–DCSK using compound chaotic sequence under alpha–mu fading channel 阿尔法-穆衰减信道下使用复合混沌序列的频率调制 NR-DCSK 性能评估
IF 1.9 4区 物理与天体物理
Pramana Pub Date : 2024-09-23 DOI: 10.1007/s12043-024-02808-0
Namrata Biswas, I Raja Mohamed, M Sangeetha
{"title":"Performance evaluation of frequency-modulated NR–DCSK using compound chaotic sequence under alpha–mu fading channel","authors":"Namrata Biswas,&nbsp;I Raja Mohamed,&nbsp;M Sangeetha","doi":"10.1007/s12043-024-02808-0","DOIUrl":"10.1007/s12043-024-02808-0","url":null,"abstract":"<div><p>This work evaluates the performance of frequency-modulated noise reduction-differential chaos shift keying (FM-NR–DCSK) when using a compound chaotic sequence (CCS) under a multipath fading channel. To construct a more complex and random CCS, the outputs of chaotic maps like the logistic map, tent map, Chebyshev map and Henon map are incorporated. In this scheme, the CCS is first frequency-modulated (FM) to generate a signal with constant energy per bit. This improves the bit error rate (BER) performance of noise reduction-differential chaos shift keying (NR–DCSK). The functionality of the CCS-based FM-NR–DCSK system is being assessed in the presence of both additive white Gaussian noise (AWGN) and alpha–mu (<i>α</i>–<i>µ</i>) fading to determine its efficacy. In conclusion, we analyse the effectiveness of the CCS compared to other existing chaotic maps.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 4","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413290","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
Cryogenic magnetocaloric properties in Xenotime-type HoPO4 氙型 HoPO4 的低温磁致性能
IF 1.9 4区 物理与天体物理
Pramana Pub Date : 2024-09-23 DOI: 10.1007/s12043-024-02831-1
Assaad Elouafi, Sara Ezairi, Fatima Lmai, Abdeslam Tizliouine
{"title":"Cryogenic magnetocaloric properties in Xenotime-type HoPO4","authors":"Assaad Elouafi,&nbsp;Sara Ezairi,&nbsp;Fatima Lmai,&nbsp;Abdeslam Tizliouine","doi":"10.1007/s12043-024-02831-1","DOIUrl":"10.1007/s12043-024-02831-1","url":null,"abstract":"<div><p>Holmium orthophosphate (HoPO<sub>4</sub>) was prepared using the solid-state method. The XRD pattern analyses have proved that HoPO<sub>4</sub> crystallises in the tetragonal structure (I4<sub>1</sub><span>(/)</span>amd). The maximum magnetic entropy change (−<span>(Delta {S}_{text{M}}^{text{max}}))</span> and the relative cooling power (RCP) reach 34.5 J<span>(/)</span>kg·K and 414.84 J kg<sup>−1</sup> at 2.4 K under a magnetic field of 50 kOe, respectively. The lowest transition temperature and the large magnetocaloric effect (MCE) showed that HoPO<sub>4</sub> is a potential candidate for superfluid helium magnetic refrigeration applications.\u0000</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 4","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413337","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
Magnon tunnelling between two magnon Bose–Einstein condensates 两个磁子玻色-爱因斯坦凝聚体之间的磁子隧道效应
IF 1.9 4区 物理与天体物理
Pramana Pub Date : 2024-09-23 DOI: 10.1007/s12043-024-02828-w
A D Belanovsky, P M Vetoshko, Yu M Bunkov
{"title":"Magnon tunnelling between two magnon Bose–Einstein condensates","authors":"A D Belanovsky,&nbsp;P M Vetoshko,&nbsp;Yu M Bunkov","doi":"10.1007/s12043-024-02828-w","DOIUrl":"10.1007/s12043-024-02828-w","url":null,"abstract":"<div><p>The rapid development of quantum magnonics can be attributed to its potential applications in quantum computing, information processing and the creation of hybrid quantum systems. Quantum quasiparticles, known as magnons, undergo Bose condensation at high densities, a phenomenon observed during radiofrequency excitation. This phenomenon was initially discovered in the antiferromagnetic superfluid <span>(^3)</span>He. Magnonic superfluidity effects, Josephson effect and magnon tunnelling were also observed in this system. Similar effects have been identified in yttrium iron garnet at room temperature, suggesting the possibility of utilising these effects in a manner akin to superconductivity. In this article, we conduct simulations of magnon tunnelling processes across the energy gap, aiming to compare these simulations with experimental findings.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 4","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413316","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
Nanoscale resistive switching behaviour and photoabsorption response from NiO nanoflakes 氧化镍纳米片的纳米级电阻开关行为和光吸收响应
IF 1.9 4区 物理与天体物理
Pramana Pub Date : 2024-09-23 DOI: 10.1007/s12043-024-02830-2
Vanaraj Solanki, Shikha Varma
{"title":"Nanoscale resistive switching behaviour and photoabsorption response from NiO nanoflakes","authors":"Vanaraj Solanki,&nbsp;Shikha Varma","doi":"10.1007/s12043-024-02830-2","DOIUrl":"10.1007/s12043-024-02830-2","url":null,"abstract":"<div><p>Hydrothermally grown NiO nanoflakes have been investigated here for their resistive switching (RS) and photoabsorption characteristics. The formation and disruption of the conducting filament (CF) under an applied external electric field leads to bistable resistive switching in the grown NiO nanoflakes. Comprehensive investigations of the <i>I–V</i> behaviour show that the formation and rupturing of the CF depend on the concentration of the metallic Ni. Interestingly, photoabsorption response demonstrates a nearly similar behaviour in UV and visible regions for nanoflakes grown at low reaction time, but an enhanced UV response for the flakes obtained at larger reaction times. These nanoflakes displaying multifunctional properties of photoabsorption and RS behaviour, that can be modulated with reaction time, are attractive for optoelectronic, electrochromic and RS-based memory applications.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 4","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413311","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
Two-proton emission within a deformed Yukawa-plus-exponential model 变形育川加指数模型中的双质子发射
IF 1.9 4区 物理与天体物理
Pramana Pub Date : 2024-09-23 DOI: 10.1007/s12043-024-02817-z
P Mehana, N S Rajeswari
{"title":"Two-proton emission within a deformed Yukawa-plus-exponential model","authors":"P Mehana,&nbsp;N S Rajeswari","doi":"10.1007/s12043-024-02817-z","DOIUrl":"10.1007/s12043-024-02817-z","url":null,"abstract":"<div><p>The Yukawa-plus-exponential model (YEM) is the modified form of liquid drop model incorporating parameter to include short-range interaction and surface diffuseness. We have studied two-proton (2p) radioactivity within the YEM for spherical nuclei in our previous work [Mehana and Rajeswari in <i>Eur. Phys. J.</i> A <b>59</b>, 104 (2023)]. The present study is the extension of the previous work to apply the model to deformed 2p emitters. Deformation is incorporated in YEM through Coulomb potential and Yukawa interaction potential. The calculated half-lives are found to have less deviation than experimental half-lives, when compared to spherical ones. Further, half-lives are also predicted for 2p emitters which are not yet studied experimentally. The calculated half-lives show good match with half-lives predicted by other theoretical models. It is seen that the half-lives of the prolate-shaped daughter nuclei are lower than spherical nuclei of the same parent, whereas the half-lives of oblate daughters are higher than that of the spherical ones.\u0000</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 4","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413317","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
Computing intelligence for the magnetised chemically reactive bidirectional radiative nanofluid flow through the Bayesian regularisation back-propagated neural network 通过贝叶斯正则化反向传播神经网络计算磁化化学反应双向辐射纳米流体流动的智能性
IF 1.9 4区 物理与天体物理
Pramana Pub Date : 2024-09-23 DOI: 10.1007/s12043-024-02794-3
Zahoor Shah, Muhammad Asif Zahoor Raja, Muhammad Shoaib, Shumaila Javeed, Taseer Muhammad, Mehboob Ali, Waqar Azeem Khan, Raja Zaki Haider
{"title":"Computing intelligence for the magnetised chemically reactive bidirectional radiative nanofluid flow through the Bayesian regularisation back-propagated neural network","authors":"Zahoor Shah,&nbsp;Muhammad Asif Zahoor Raja,&nbsp;Muhammad Shoaib,&nbsp;Shumaila Javeed,&nbsp;Taseer Muhammad,&nbsp;Mehboob Ali,&nbsp;Waqar Azeem Khan,&nbsp;Raja Zaki Haider","doi":"10.1007/s12043-024-02794-3","DOIUrl":"10.1007/s12043-024-02794-3","url":null,"abstract":"<div><p>This research work aims to explain the model and assessment of a differential mathematical system of the magneto-bioconvection of the Williamson nanofluid model (MBWNFM) by capitalising on the strength of the stochastic technique through computational intelligence of Bayesian regularisation back-propagated neural networks (CIBRB-NNs). This facilitates a more accurate, reliable and proficient computation of the dynamics. A reference dataset is built using the Adams technique in the Mathematica software to depict multiple situations and account for numerous influential parameters of the MBWNFM. The reference data results are split into 70% for training and 30% for validation and testing methods. This approach aims to enhance the accuracy of the approximated results and enable them to be compared with established solutions. The demonstration of the accuracy and efficiency of the created CIBRB-NNs involves a comparison of the results obtained from the dataset using the Adams approach, by adjusting several influential parameters which include magnetic parameter (<span>(M)</span>), bioconvection Lewis Number (<span>(L_{b})</span>), thermal diffusivity (<span>(alpha)</span>) and thermal Biot number (<span>(gamma)</span>). The stability and accuracy of CIBRB-NNs are validated using various methodologies, including the analysis of fitness curves depicting mean square error, regression studies, evaluation of error using histogram plots and measurement of absolute errors. The excellent measures of performance in terms of MSE are achieved at levels 4.50e-12, 6.73e-13, 1.07e-13, 7.08e-13, 4.77e-13 and 1.70e-13 against 82, 150, 98, 83, 170 and 189 epochs. The error analysis of the proposed and reference datasets shows that CIBRB-NNS is authentic and precise, ranging from e-09 to e-04 for all scenarios.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 4","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142413310","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
Dynamic analysis and chaos control of a unified chaotic system 统一混沌系统的动态分析和混沌控制
IF 1.9 4区 物理与天体物理
Pramana Pub Date : 2024-09-13 DOI: 10.1007/s12043-024-02744-z
Xia Wu, Xiaoling Qiu, Limi Hu
{"title":"Dynamic analysis and chaos control of a unified chaotic system","authors":"Xia Wu,&nbsp;Xiaoling Qiu,&nbsp;Limi Hu","doi":"10.1007/s12043-024-02744-z","DOIUrl":"10.1007/s12043-024-02744-z","url":null,"abstract":"<div><p>Two different control methods are proposed in this paper to effectively control the chaotic phenomenon of nonlinear dynamical system. One is a new Hamilton energy feedback control method based on Helmholtz’s theorem, which reduces the Lyapunov exponents value of the system by adjusting the feedback gain for controlling chaos. The other is to control the chaos of the system by using delayed feedback control method. Based on this method, we consider the local asymptotic stability of the equilibrium point of the system, and give conditions for the existence of the Hopf bifurcation of the system and the stability domain of the delay parameters. By using the centre manifold theorem and the Poincare normal form method, specific formulas for determining the direction of Hopf bifurcation and the stability of the bifurcation periodic solutions are derived. Finally, the simulation results show that chaos can be controlled by choosing appropriate time-delay parameters.\u0000</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 4","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204334","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
Gravastars in the Lyra geometry 天琴座几何中的引力星
IF 1.9 4区 物理与天体物理
Pramana Pub Date : 2024-09-11 DOI: 10.1007/s12043-024-02815-1
A T Shafeek, M A Bakry, G M Moatimid
{"title":"Gravastars in the Lyra geometry","authors":"A T Shafeek,&nbsp;M A Bakry,&nbsp;G M Moatimid","doi":"10.1007/s12043-024-02815-1","DOIUrl":"10.1007/s12043-024-02815-1","url":null,"abstract":"<div><p>This paper explores the evolution of gravastars within the context of the Lyra geometry. The mathematical formulations of the three regions of a gravastar: (i) the inside region, (ii) the shell region and (iii) the external void region are described separately, along with their physical characteristics and graphical representations. The study explores different aspects of our model by analysing the behaviour of physical parameters. It solves the modified Einstein’s field equations, which are derived from this geometry, under the conditions of gravastar formation. The investigation focusses on the physical properties of the shell region, such as energy density, proper length, full energy, entropy, surface tension, thinness and energy conditions. Additionally, the stability of the gravastar model is examined by analysing the surface red-shift in relation to the shell length.</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 4","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204336","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
On universality of clustering in natural evolution of particle systems: taking human languages as an example 论粒子系统自然进化中聚类的普遍性：以人类语言为例
IF 1.9 4区 物理与天体物理
Pramana Pub Date : 2024-09-11 DOI: 10.1007/s12043-024-02822-2
Yu Zhang, Chen Diao, Ning Cai
{"title":"On universality of clustering in natural evolution of particle systems: taking human languages as an example","authors":"Yu Zhang,&nbsp;Chen Diao,&nbsp;Ning Cai","doi":"10.1007/s12043-024-02822-2","DOIUrl":"10.1007/s12043-024-02822-2","url":null,"abstract":"<div><p>Computer model has been extensively adopted to overcome the time limitation of language evolution by transforming language theory into physical modelling mechanism, which helps to explore the general laws of evolution. In this paper, a model is designed to simulate the evolution process of languages in human settlements, with the associated network topology being lattice. The language of each node in the lattice will evolve gradually under the influence of its own fixed evolutionary direction and neighbours. According to the computational experiment results, it is discovered that the state points of languages always converge into several clusters during the evolution process, which gives us an insight into language evolution.\u0000</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 4","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204337","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
Analysis, microcontroller implementation and chaos control of non-smooth air-gap permanent magnet synchronous motor 非平滑气隙永磁同步电机的分析、微控制器实现和混沌控制
IF 1.9 4区 物理与天体物理
Pramana Pub Date : 2024-09-11 DOI: 10.1007/s12043-024-02799-y
Giles Yamdjeu, Balakrishnan Sriram, Sifeu Takougang Kingni, Karthikeyan Rajagopal, Alidou Mohamadou
{"title":"Analysis, microcontroller implementation and chaos control of non-smooth air-gap permanent magnet synchronous motor","authors":"Giles Yamdjeu,&nbsp;Balakrishnan Sriram,&nbsp;Sifeu Takougang Kingni,&nbsp;Karthikeyan Rajagopal,&nbsp;Alidou Mohamadou","doi":"10.1007/s12043-024-02799-y","DOIUrl":"10.1007/s12043-024-02799-y","url":null,"abstract":"<div><p>This article presents an analysis and control approach for a non-smooth air-gap permanent magnet synchronous motor (NSAG-PMSM) in the absence of external disturbances. The analytical study of NSAG-PMSM shows the existence of equilibrium points. Based on the Routh–Hurwitz criterion, the stability of the equilibrium points reveals the existence of transcritical bifurcation. NSAG-PMSM exhibits various dynamical behaviours, such as bistable chaos, periodic spiking oscillations, chaotic spiking characteristics, coexistence between periodic and chaotic behaviours and periodic evolution towards monostable chaos as system parameters change. The research uses microcontroller implementation to validate the dynamical characteristics observed during the numerical simulations of the NSAG-PMSM. The study of NSAG-PMSM proposes a strategy to mitigate chaos and stabilise the system using two simple controllers, with a comparative study presented using peak overshoot and settling time diagrams. By combining these different aspects, this article significantly contributes to the understanding of the operation in NSAG-PMSM, highlighting specific aspects related to the application of microcontroller techniques in the field of electrical engineering and solutions to chaos control.\u0000</p></div>","PeriodicalId":743,"journal":{"name":"Pramana","volume":"98 4","pages":""},"PeriodicalIF":1.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204335","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
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