International Journal of Modern Physics B

In this work, we discuss the synthesis, characterization and dielectric properties of Bi${}_{0.9}$La${}_{0.1-x}$(Ba/Sr)${}_x$FeO₃ [$x=0,0.05$] ceramic compounds. These samples were synthesized via a solid-state reaction method and then characterized for structural analysis exploiting the X-ray diffraction (XRD) technique. The Rietveld refinement data inferred that all the prepared samples were acquired a monoclinic phase with space group C1c1. Field emission scanning electron micrographs (FE-SEM) images of the samples indicated highly grown grains with a moderate level of grain boundary development across the sample. The energy dispersive analysis of the X-ray (EDAX) diffraction spectra analysis confirmed that the composition was free from foreign impurities. Further, UV–Vis experiment was conducted and estimated average value of optical bandgap was about 2.2 eV, which is highly recommended for photocatalytic and opto-electronic device applications. Room-temperature dielectric studies revealed that samples were extremely good dielectric materials with low dielectric loss, which is important for storage device applications. In addition, the depressed semicircles obtained from impedance analysis indicated that the samples exhibited distributed relaxation times and non-Debye behavior.

Advanced research frontiers are extended from biophysics relations on the Earth upto the discovering any type of alive matter within the whole space. Microorganisms’ motion within the molecular biology processes integrates variety of microorgnisms functions. In continuation of our Brownian motion phenomena research, we consistently build molecular-microorganisms structures hierarchy. We recognize everywhere biomimetic similarities between the particles in alive and nonalive matter. The research data are based on real experiments, without external energy impulses. So, we develop the analysis, inspired by fractal nature Brownian motion, as recognized joint parameter between particles in alive and nonalive biophysical systems. This is also in line with advance trends in hybrid submicroelectronic integrations. The important innovation in this paper is that we introduced approximation of trajectory and error calculations, using discrete mean square approximation, what cumulatively provide much more precise biophysical systems parameters. By this paper, we continue to generate new knowledge in direction to get complex relations between the particles clusters in biophysical systems condensed matter.

In this paper, we investigate head-on and overtaking collisions of two solitary waves propagating in two-dimensional (2D) hexagonal packing confined in a rectangular region, using the fifth-order Runge–Kutta numerical scheme. In the head-on collision, numerical results indicate that the velocity amplitude of the solitary waves and the second solitary waves is proportional to the impacting velocity of the solitary waves. The relationship between phase shift and impacting velocity satisfies the equation $\mathrm{\Delta }t\sim {(V_{\mathrm{\text{Le}}})}^P$. For head-on collisions of the waves with an equal amplitude of velocity, this power exponent is $P=-0.202$, which can be well predicted by the binary collision approximation theory. For the case of head-on collisions between the waves with unequal amplitudes of solitary waves, this power exponent becomes $P=-0.656$. During an overtaking collision, the fast solitary wave has a positive phase shift, and the slow solitary wave has a negative phase shift. The phase shift of the fast solitary wave also has a power exponential relationship with the impacting velocity. The two waves either form a single peak in transition, or remain separated throughout the encounter with a double-peak formation depending on the ratio of the impacting velocity of solitary waves. The critical condition between the two regimes is consistent with those obtained by the Korteweg–de Vries model.

The nanofluids’ job is fundamental in the cooling of miniature electronic gadgets including microchips and associated gizmos. Having such interesting and useful applications of nanofluids in mind our objective is to deliberate the melting heat transfer impact in the flow of a Casson nanofluid past a stretched cylinder in a spongy medium. The stability of the nanoparticles is ascertained by considering the impact of the gyrotactic microorganisms. The entropy generation minimization analysis is also part of this study. A bvp4c built-in function of the MATLAB software is engaged to find the solution of the system of a nonlinear system of equations numerically. The consequences of the primary parameters versus emerging profiles are depicted and conversed in the view of their physical importance. The melting heat transfer parameter poses an opposing trend against the fluid velocity and temperature. Further, the gyrotactic microorganism distribution is lowered for the Peclet number. The entropy generation is enhanced for the sizeable estimates of the Reynolds and Brinkman numbers.

An effective and reliable evolution model can provide strong support for the planning and design of transportation networks. As a network evolution mechanism, link prediction plays an important role in the expansion of transportation networks. Most of the previous algorithms mainly took node degree or common neighbors into account in calculating link probability between two nodes, and the structure characteristics which can enhance global network efficiency are rarely considered. To address these issues, we propose a new evolution mechanism of transportation networks from the aspect of link prediction. Specifically, node degree, distance, path, expected network structure, relevance, population and GDP are comprehensively considered according to the characteristics and requirements of the transportation networks. Numerical experiments are done with China’s high-speed railway network, China’s highway network and China’s inland civil aviation network. We compare receiver operating characteristic curve and network efficiency in different models and explore the degree and hubs of networks generated by the proposed model. The results show that the proposed model has better prediction performance and can effectively optimize the network structure compared with other baseline link prediction methods.

In this paper, we investigate two different constant-coefficient nonlinear evolution equations, namely the Schamel Burgers equation and the Schamel equation. These models also have a great deal of potential for studying ion-acoustic waves in plasma physics and fluid dynamics. The primary goal of this paper is to establish closed-form solutions and dynamics of analytical solutions to the Schamel Burgers and the Schamel equations, which are special examples of the well-known Schamel–Korteweg-de Vries (S-KdV) equation. We derive completely novel solutions to the considered models using a variety of computation programmes and a newly proposed extended generalized $(\frac{G^{\prime }}{G})$ expansion approach. The newly formed solutions, which include hyperbolic and trigonometric functions as well as rational function solutions, have been produced. The annihilation of three-dimensional shock waves, periodic waves, single soliton, singular soliton, and combo soliton, multisoliton as well as their three-dimensional and contour plots are used to show the dynamical representations of the acquired solutions. These results demonstrate that the proposed extended technique is efficient, reliable and simple.

Frequent changes in power grid topology bring risks to the stable operation of power systems. It is essential to identify changes in the power grid topology quickly and accurately. This paper presents a novel method named network reduction-based topology change identification (NR-TCI) algorithm to identify topology changes in multi-machine power systems. The proposed algorithm can quickly identify power grid topology changes using only phasor measurement unit (PMU) data sampled during the system’s transient process. The NR-TCI algorithm uses the network order reduction method to reduce the order of a bus admittance matrix and then uses PMU measurement data to estimate the reduced admittance matrix by least square method. Finally, the reduced admittance matrix is adopted to find topological information, and the Sherman–Morrison formula is utilized to identify the topology changes. The effectiveness of the proposed NR-TCI algorithm is verified with a case study of a 3 machine 9 bus system in Matlab. In addition, the influence of PMU sampling frequency on the effectiveness of the proposed algorithm is also studied.

MnCo₂O₄/g-C₃N₄ composite material was synthesized by the hydrothermal method, compared with MnCo₂O₄ without g-C₃N₄, it has excellent electrochemical performance. The composite material can reach a specific capacitance of 350 Fg${}^{-1}$ at 1 Ag${}^{-1}$. The capacity retention rate is 96% after 1000 cycles at the rate of 2 Ag${}^{-1}$. Experiments show that g-C₃N₄ can effectively disperse and improve the conductivity of urchin-like MnCo₂O₄, and the composite of sufficient g-C₃N₄ can give full play to the performance of urchin-like MnCo₂O₄, provide faster electronic transport channels, effectively improve the ion migration rate, and make urchin-like MnCo₂O₄ increase the rate performance under high charge and discharge rates.

Two-layer fluid models are used to depict some nonlinear phenomena in fluid mechanics, medical science and thermodynamics. In this paper, we investigate a (3$+$1)-dimensional Yu-Toda-Sasa-Fukuyama equation for the interfacial waves in a two-layer liquid or elastic quasiplane waves in a lattice. Via the Kadomtsev-Petviashvili hierarchy reduction, we derive the rational solutions in the determinant forms and semi-rational solutions. The $n$th-order lump waves and multi-lump waves are obtained, where $n$ is a positive integer. We observe the second-order lump waves: Two-lump waves interact with each other and separate into two new lump waves. Two-lump waves are observed: Overtaking interaction takes place between the two-lump waves; After the interaction, the two-lump waves propagate with their original velocities and amplitudes. Studying the semi-rational solutions, we show the fusion between a lump wave and a bell-type soliton and fission of a bell-type soliton. Interaction between a line rogue wave and a bell-type soliton is shown.

In this paper, the effects of glass-ceramics sintering aid, La₂O₃–B₂O₃–CaO–P₂O₅ (LBCP), on the sinterability, microstructure, and microwave dielectric properties of 0.5(Ca${}_{0.7}$Nd${}_{0.2})$TiO₃–0.5(Li${}_{0.5}$Nd${}_{0.5})$TiO₃ (CNT–LNT) ceramic have been investigated. The results indicated that LBCP glass-ceramics has good wettability to CNT–LNT (contact angle at 980${}^{\circ }$C is 31.9${}^{\circ }$), and it can be used as an effective sintering aid to reduce the sintering temperature of CNT–LNT ceramic from 1300${}^{\circ }$C to 980${}^{\circ }$C. LBCP glass-ceramics did not change the main crystal phase (perovskite structure) of the sample, but a small amount of LaBO₃ and LaPO₄ phases was precipitated. Since the LaBO₃ and LaPO₄ phases are low-loss phases, it is believed that the crystal phases can improve the dielectric properties of the sample, especially the dielectric loss. The samples with 10 wt.% of glass additive sintered for 4 h at 980${}^{\circ }$C exhibit the optimized properties: a high dielectric constant of 80.8 and a $Q\times f$ value of 2031 GHz. The high ${𝜀}_r$ and $Q\times f$ value, coupled with a relatively low sintering temperature, suggest that the optimized compositions have the potential to be used in microwave low-temperature co-fired ceramics applications.

In this paper, the modified Jacobi elliptic function method is applied for Salerno equation which describes the nonlinear discrete electrical lattice in the forbidden bandgaps. Dark and bright solitons are obtained. Also, periodic solutions and periodic Jacobi elliptic function solutions are reported. Moreover, for the physical illustration of the obtained solutions, three-dimensional and two-dimensional graphs are presented.