International Journal of Modern Physics B

This study describes a novel application of artificial intelligent-based computing paradigm via knacks of neural networks backpropagated through Levenberg–Marquardt scheme (NNs-BLMS) to investigate the mathematical model of Carreau nanofluid thin film flow over a stretching sheet under the magnetic field effect (CNTFFSSM). The system of PDEs of the designed model is transformed by using suitable transformations to the system of ODEs. The Adams deterministic numerical technique is utilized for generation of a dataset for the proposed technique for six varients to produce corresponding six scenarios of the designed model by varying magnetic parameter, Brownian motion parameter, unsteadiness parameter, Weissenberg number, thermophoresis number and Lewis number. The computational intelligent solver NNs-BLMS is applied to the CNTFFSSM model by performing processes on training, testing and validation samples. The efficiency of the proposed technique is validated by comparison of the standard solution and outcomes of the proposed solver for designed model through histograms, error analysis and regression analysis. The outcomes disclosed that velocity field is a decreasing function of magnetic parameter, while an increasing function of the Weissenberg number. The temperature and concentration profiles enhance with higher thermophoresis parameter, while diminish with higher Weissenberg number. Moreover, higher Lewis number causes lower concentration profile.

Gupta and Density Functional Theory (DFT) calculations were performed to investigate of structural and magnetic behaviors of 19 atom Fe_nRh${}_{19\text{-}n}$ ($n=0$–19) nanoalloys. A double icosahedron structure was considered for Fe_nRh${}_{19\text{-}n}$ ($n=0$–19) nanoalloys. Significantly, the effects of Fe atom addition on the chemical ordering, stability and total magnetic moments of the nanoalloys were investigated. Local optimization results at the Gupta level show that the Fe atoms are located in the center of the double icosahedron structure and finally in the equatorial region on the surface. The mixing energy analysis obtained that Fe${}_{12}$Rh₇ and Fe₄Rh${}_{15}$ nanoalloys are the most stable compositions at Gupta and DFT levels, respectively. It was found that Fe_nRh${}_{19\text{-}n}$ ($n=0$–19) nanoalloys are energetically suitable for mixing at both Gupta and DFT levels. Also, the bond order parameter result is compatible with the mixing energy analysis result. The total magnetic moments of the Fe_nRh${}_{19\text{-}n}$ ($n=0$–19) nanoalloys increase with the addition of the Fe atom, which is a ferromagnetic metal.

In this paper, a potential scheme to produce both the harmonic spectral continuum and single harmonic has been proposed and investigated by using the combined chirped pulses. It is found that with the proper combination of the two-color second-order chirped pulse, both the harmonic spectral continuum and single harmonic can be obtained. Further, with the introduction of the third pulse, the harmonic yield can be enhanced. However, the single harmonic generation is almost independent on the chirp of the third pulse. As a result, the isolated attosecond pulses (IAPs) of sub-40 as can be obtained from the harmonic spectral continua and the adjustable single harmonics from 194th order to 360th order can also be found. While with the introduction of the third-order or fourth-order chirped pulses, only the harmonic spectral continua can be obtained. The generations of the harmonic spectral continua and single harmonics have been analyzed by using the three-step theory and the time-profiles of the harmonic generation.

This article proposes a new refined definition of light, which makes it possible to harmonize the wave and corpuscular concepts of this object of matter and quantitative relations that describe the wave-corpuscular nature of the phenomena of interference, diffraction, dispersion, polarization, external and internal photoeffects as phenomena as well as such electroluminescence and photoluminescence associated with light.

A new model of human flesh search (HFS) was established based on the love-triangle model (LTM) and susceptible-infected-recovered (SIR) model. The competitive propagation process between rumors and true messages in HFS was investigated. According to the proposed model, the equation was derived to describe the propagation of rumors and true messages in HFS. Coupling effect of rumors and true messages and the node credibility were considered; the simulations were implemented on small world network. The results show that the competition probability initial value of rumors is higher than that of true messages in the process of HFS. The coupling effect indicates that the spreading of one information fragment would be influenced by others. Furthermore, the inhibition of credibility on rumor spreading is found. Therefore, the means of suppressing rumors is proposed furtherly. Finally, the validity of the new model was verified through the comparative experiment between the simulation of the proposed model and real case.

In this work, a one-dimensional waveguide is formed by virtue of the helium ion implantation in the oxyfluoride glass (OFG). The energy and the fluence of the ion implantation are 0.4 MeV and $6.0\times 10^{14}$ ${\mathrm{\text{He}}}^{+}\cdot {\mathrm{\text{mm}}}^{-2}$, respectively. The m-line curve with the effective refractive indices of the modes was recorded by using the prism coupling system. The energy loss distribution and the refractive index profile were calculated by the stopping and range of ions into matter (SRIM)-2013 and the RCM, respectively. The light modal profile was measured by the end-facet coupling system. It suggests that the He${}^{+}$-ion implanted OFG waveguides have the potential to act as integrated photonic devices.

The application of lithium iron phosphate (LiFePO₄) was still hindered by its poor high rate performance. Surface coating had proven to be an effective strategy to solve these problems. However, the previous surface coating method made the synthesis process more complicated. In this work, a simple organic salt decomposition method was developed to prepare LiFePO₄@Ni cathode material (LFP@Ni). Scanning electron microscope (SEM), X-ray diffractometer (XRD) energy disperse spectroscopy (EDS) confirmed that a uniform nickel-coated composite structure had been successfully constructed without changing the crystal structure. The charge and discharge test showed that after 200 cycles at 5C, LFP@Ni maintained a discharge specific capacity of 65.02% and the exchange current density was 1.3 times that of LFP. Compared with LFP and LFP-Ni, the composite cathode LFP@Ni had better cycle capacity. This improvement was attributed to the good conductivity of nickel, which can quickly conduct electrons in the LFP cathode material, thereby improving the dynamic performance of the LFP cathode material.

Nanofluid and magnetic field impacts are significant in bioengineering and medical treatment. The effectiveness of gold particles in blood flow (Sisko fluid flow) with nonlinear thermal radiation and heat source over a curved surface is investigated in this work. The partial slip influence is utilized to explore the characteristics of nanofluid flow in depth. The Sisko model’s first-order partial differential equations (PDEs) are simplified to ordinary differential equations (ODEs) by employing suitable variables. The findings are displayed by using the bvp4c (shooting approach) in MATLAB. When compared to earlier reports, the accuracy is found to be satisfactory. In addition to the influence of a magnetic field and radiation, although both are useful in therapeutic hyperthermia, the magnetic field reduces the velocity distribution. The velocity profile is boomed for the estimations of slip parameter while declined for the suction parameter. The thermal profile is boosted up for the higher magnitude of temperature ratio parameter and Biot number. The thermal profile is decreased for the greater values of the suction parameter while increases for the heat source parameter.

Polar optical phonon modes of a wurtzite nitride trianglar quantum dot (QD) are deduced and analyzed by using the dielectric continuum model. Based on a method of nonseparable variables, the Laplace equation of electristatic potential of the structure is solved, and the exact and analytical phonon states of exact confined (EC) modes are derived. It is found that the frequency of EC modes in the nitride trianglar QD systems can take both the longitudinal optical phonons in $z$-direction ${\omega }_{z,L}$ and the longitudinal optical phonons in $xy$-plane ${\omega }_{t,L}$, which is obviously different from the cases of EC modes in wurtzite GaN quantum wells and quantum wires due to their different confined dimensions. The polarization eigenvectors and their orthogonality relations for the EC phonon modes are derived, which could form a set of orthogonal and completed basis vectors. By using the orthogonality relations of polarization eigenvector and field quantization method, the free phonon field of EC modes and the corresponding Fröhlich electron–phonon interaction Hamiltonian are obtained. Numerical calculations on a wurtztie GaN trianglar QD are performed. The spatial distributions of phonon potentials of EC phonons both in $xy$-plane and in $z$-direction as well as the electron–phonon coupling strength are plotted and discussed. It is observed that the potential of these EC phonon modes is strictly confined within the trianglar QD ranges. The dependence of symmetries and electron–phonon coupling strength on the quantum numbers $p$ and $q$ in $xy$-plane, and the quantum number $m$ in $z$-direction are analyzed in detail. The relationship of the total number of peaks and troughs with these quantum numbers are also discussed and induced.

Hybrid synapses widely exist in the brain neural system, but how memristive and plastic chemical synapses cooperatively modulate the collective dynamics of neurons remains largely unknown. Here, we constructed self-organized networks with two heterogeneous FitzHugh–Nagumo (FHN) neurons coupled with memristive and chemical synapses, wherein the chemical synapse is modulated by the spike-timing-dependent plasticity (STDP) rule. Additionally, three kinds of network models involving excitatory–excitatory ($E$–$E)$ neurons, high excitatory–inhibitory (high $E$–$I$) neurons and low excitatory–inhibitory (low $E$–$I$) neurons were constructed. The modulation of memristive synapses on the structure and dynamics of self-organized neuronal networks is greatly dependent on model selection. Stronger coupling of memristive synapses induces consistently more stable network structure and enhanced network synchronization in the $E$–$E$ and high $E$–$I$ models but has complex effects on the low $E$–$I$ neuronal network. In contrast, increasing the closing rate of memristive synapses has little effect on the $E$–$E$ and high $E$–$I$ networks but can accelerate the self-organization process and result in more complex firing patterns and weaker synchronization in the low $E$–$I$ network. These results provide further understanding of the mechanism of the self-organized neuronal network dynamics underlying hybrid synapses and neuronal excitation.