International Journal of Modern Physics B

Photonic crystal is a dielectric structure arranged according to certain rules, and its excellent electromagnetic wave characteristics can be used to manufacture a lot of kinds of photonic crystal devices. In this paper, a defect is introduced into the photonic crystal, and the transfer matrix method is used to study the relationship between the liquid concentration and the peak value of the liquid transmission at the electromagnetic wave length when the defect is a mixture of ethanol and glycol. The results show that by observing and measuring the position of the peak transmittance of the mixed liquid, the substance content of the liquid mixture, that is, the concentration, can be inferred. The accuracy of this method is compared with the experimental results, which shows that this method has high accuracy. This method is simple and easy to operate. This result opens up a new direction for the application of photonic crystals.

The urban rail network system plays a significant role in the urban transportation system and urban economic development. Further study of the urban rail network properties can provide additional guidance to related scholars and designers. This study explored urban rail network properties worldwide, including assessments of their static and dynamic network topologic characteristics. Statically, this study analyzed various related network topological indicators for all of these urban rail networks. We found that, with increasing network size, the average degree slightly increases while the complexity and connectivity decrease. Using the Kolmogorov–Smirnov goodness-of-fit, the scale of the degree interval of these cities is [3.5 12.2]. Approximately 90% of these cities have network efficiency values less than 0.12, and 78% of these cities have lower assortativity coefficients. Focusing on the sustainable growth of rail networks, this study tested some specific networks to further deliberate their network expansion ability, network growth, and network robustness properties. The network expansion capability of small networks is relatively poor, while that of large networks is relatively strong. A simulation of network growth suggests that the connection of nodes with the maximum path length will seriously affect the efficiency and characteristics of the network. The robustness of the network indicates that adopting the maximum nodal degree elimination strategy will affect the function of the network. The results provide essential reference information for the rational planning, structural optimization, safe operation and sustainable growth of rail transit networks.

The transport mechanism of water molecules on the surface of single-layer $\beta$-graphyne is investigated from the first-principles calculations. The result indicates that when water molecules are adsorbed in different stances, their corresponding transport paths are different. When N atoms are doped with sp carbon atoms, the transport pathway of water molecules is opposite to that of intrinsic $\beta$-graphyne, which is due to the charge transfer between atom s. Consequently, this study is conducive to understand the mechanism of nanoscale water transport on the graphyne surface and provides a theoretical basis for exploring the interaction between water and graphyne.

In this paper, we study the $N$-soliton solutions for the Hirota and Maxwell–Bloch equation with physical meaning. From the Lax pair and Volterra integral equations, the Riemann–Hilbert problem of this integrable equation is constructed. By solving the matrix Riemann–Hilbert problem with the condition of no reflecting, the $N$-soliton solutions for the Hirota and Maxwell–Bloch equation are obtained explicitly. Finally, we simulate the three-dimensional diagram of $\left|E\right|$ with 2-soliton solutions and the motion trajectory of $t$-axis in the case of different $z$.

We show that the quantum interference between two spontaneous emission channels can be significantly enhanced when a three-level V-type atom is placed near the surface of the topological insulator ${\mathrm{\text{Bi}}}_2{\mathrm{\text{Se}}}_3$. The enhancement of quantum interference is a result of the strong dependence of the spontaneous emission rate on the orientation of an atomic dipole relative to surface of the ${\mathrm{\text{Bi}}}_2{\mathrm{\text{Se}}}_3$ at the frequencies of polaritonic-type excitations.

Undoped and manganese (Mn)-doped zinc oxide (ZnO) thin films have been deposited onto glass substrates at 300${}^{\circ }$C using a low cost spray pyrolysis technique. Structural, optical and electrical properties of the as-deposited films have been investigated. Scanning electron microscopy images show the existence of clusters with well-defined nucleation centers consisting of highly dense ganglia-like fibers over a large area around the nucleation center. Chemical compositions of the ZnO and Mn-doped ZnO thin films are studied by using energy dispersive X-ray (EDX) analysis. X-ray diffraction spectra depict that the films have polycrystalline wurtzite structure. The average crystallite sizes are calculated in the range of 8–16 nm by Williamson–Hall method and found in good agreement with Scherer method. Optical transmittance of the films is about 80% in the visible region. Bandgap energy is tuned to 2.83 eV from 3.10 eV with increasing Mn doping. Electrical resistivity at room-temperature decreases significantly with increasing Mn doping as well as increasing temperature from 300–440 K. The activation energies in the temperature ranges 300–350 K and 350–440 K are found to be in the range of 0.25–0.16 eV and 0.35–0.59 eV, respectively. Hall Effect measurements show that the thin films have negative Hall co-efficient indicating $n$-type conductivity at room-temperature. Carrier concentration is found to be of the order of 10${}^{18}$ cm${}^{-3}$.

Image fusion can be used to improve the image utilization, spatial resolution and spectral resolution, which has been widely applied on medicine, remote sensing, computer vision, weather forecast and military target recognition. The goal of image fusion is to reduce the uncertainty and redundancy of the output and increase the reliability of the image on the basis of the maximum combination of relevant information. In this paper, a multi-focus image fusion algorithm based on WNMF and Focal point position analysis is proposed to improve the image fusion method based on nonnegative matrix factorization. In the imaging process, the Gaussian function is used to approximate the point spread function in the optical system. Then calculate the difference between the original image and the approximate point spread function and get the weighted matrix $U$. Finally, we apply the weighted nonnegative matrix algorithm to image fusion, and the new fusion image with clear parts is obtained. Experimental results show that the multi-focus image fusion algorithm based on WNMF and Focal point position analysis (MFWF) is better.

In this paper, we sketch and scrutinize the solitonic wave solution of Camassa–Holm equation by applying Kudryashov’s new method. We promote the algorithm of our new method to find the new solutions of this essential model. Camassa–Holm equation is a recent model in the point of distortion of hierarchies composition of integrability systems. It has been displayed that these solutions have the shape of dark, bright and singular solitons solutions of Camassa–Holm nonlinear Schrodinger equation. Graphically changing of extracted results of this model (CH) has been separated to grasp the substantial evolution. We analyze the sensitivity of the obtained solutions on behalf of different boundary conditions. It is fair that our model furnishes an impressive mathematical mechanism for manufacturing the solutions of the traveling wave for many models in physics and mathematics. The strategy utilized here is straightforward and succinct.

Tunneling corrections on Kramers escape rates with power-law distribution in three damping systems are obtained separately based on flux over population theory by introducing the tunneling correction into flux. Two common barriers (Eckart barrier and parabolic barrier) are used to calculate tunneling corrections. We take the relevant parameters from the $\mathrm{\text{H}}+{\mathrm{\text{H}}}_2$ reaction to further study how the tunneling correction affects the escape rates in three damping cases. It shows that the tunneling correction has great impact on escape rate in low damping and overdamped systems, but has little impact in low-to-intermediate damping (LID) system. Heretofore, we extend our previous work to a wider range of application areas.

Elastic metamaterials (EMs) are a new kind of artificial composite medium composed of complex micro-structural elements, which have unique dynamic properties and elastic wave regulation ability that their constituent materials do not possess. The existing researches on EMs mainly focus on wave characteristics in two-dimensional and three-dimensional infinite domains. However, actual EM structures are always in the form of finite structures such as rods, beams and plates, so it is more important for engineering applications to understand and master their natural and forced vibration characteristics. Therefore, it is necessary to establish an effective simplified solution method and framework with certain accuracy for the vibration analysis of such structures. In the early stage, we have studied the natural and forced vibration characteristics of EM beams from this point of view, and presented a simplified solution process. In this paper, a kind of sandwich beam structure with EMs as the core is further constructed, the simplified solution process is extended to such more practical model analysis, and the free and steady forced vibration analysis processes of the finite-size sandwich beam are given. The vibration characteristics different from the traditional sandwich beam are investigated, and some interesting and useful phenomena are revealed, including the absence of natural frequencies within bandgap (BG), the gathering of natural frequencies in the vicinity of band edges, and the particular modal correspondence before and after BG. Then, the corresponding formation mechanisms are explained from the perspective of wave propagation.