Modern Physics Letters B

In network science, link prediction is a technique used to predict missing or future relationships based on currently observed connections. Much attention from the network science community is paid to this direction recently. However, most present approaches predict links based on ad hoc similarity definitions. To address this issue, we propose a link prediction algorithm named Transferring Similarity Based on Adjacency Embedding (TSBAE). TSBAE is based on network embedding, where the potential information of the structure is preserved in the embedded vector space, and the similarity is inherently captured by the distance of these vectors. Furthermore, to accommodate the fact that the similarity should be transferable, indirect similarity between nodes is incorporated to improve the accuracy of prediction. The experimental results on 10 real-world networks show that TSBAE outperforms the baseline algorithms in the task of link prediction, with the cost of tuning a free parameter in the prediction.

Two simple polarization-independent electromagnetically-induced transparency (EIT) metamaterials are numerically and experimentally demonstrated at the terahertz region. The first structure is composed of two metal concentric rings on a substrate, while the second one is composed of one metal ring with a cross in it. The bright–bright coupling behavior appears in the two symmetric polarization-independent EIT structures while it is generally observed in asymmetrically structures. In addition, the large group index is extracted to verify the slow-light effect of the two EIT structures. These simple EIT structures may have potential applications in certain areas, including sensing, slow-light and filtering devices.

The supersymmetric variable-coefficient KdV equation is presented and it admits Painlevé property by the standard singularity analysis. Based on Hirota bilinear method and Riemann theta function, one and two quasi-periodic wave solutions for the supersymmetric variable-coefficient KdV equation are studied. In addition, we give the asymptotic relations between quasi-periodic wave solutions and soliton solutions.

With further research, the theory of local discrimination of orthogonal product states (OPSs) becomes more and more perfect. In this paper, we present a quantum proxy signature (QPS) scheme based on a set of OPSs that cannot be exactly discriminated by local operations and classical communation (LOCC). Our scheme possesses all the properties of QPS. More importantly, no one can obtain any meaningful information of a signature owing to the different particles of an OPS are separately transmitted. We show that our scheme is secure by a detailed security analysis.

A multi-channel Fano resonant structure is proposed and analyzed based on subwavelength metal–insulator–metal (MIM) waveguides. First, two MIM output ports associated with specific side-coupled cavities are designed to locate at the center and quarter positions of an end-coupled cavity, respectively. Since the interference between the dark and bright modes, dual-channel Fano resonances with asymmetrical lines shapes are obtained at both ports, respectively. High sensitivity and figure of merits are investigated. Besides, phase shifts are also investigated leading to positive and negative group delays available at the Fano peaks and dips, respectively. Likewise, two extra output ports with identical resonant cavities are placed on the other side of the end-coupled cavity. In this case, four-channel Fano resonances with considerable performances are obtained. The proposed structure is analyzed by the coupled mode theory and the finite difference time domain method. It is believed this device can be used as a chip-scale refractive index sensor and optical filter.

This paper deals with the study of optical solitons in the presence of new linear and nonlinear parity-time $({𝒫}{𝒯})$-symmetric modulation lattices. The nonlinear medium is a derivative term with arbitrary power. Inverse engineering scheme is utilized to retrieve bright, dark, dipole and singular soliton solutions. These solutions are presented for four new ${𝒫}{𝒯}$-symmetric potentials. The results reveal that optical bright, dark and dipole solitons can exist for those new physical settings.

An optically transparent metamaterial absorber (MMA) has been demonstrated numerically and experimentally at the S-band. The designed MMA is composed of polymethyl methacrylate (PMMA), indium-tin-oxide (ITO) attached to polyethylene terephthalate (PET) film, and numerically provides effective absorption with reflection loss lower than −10 dB in the frequency range of 1.85–4.65 GHz. Experimental measurement shows the reflection loss of the proposed MMA is better than −10 dB from 2.00 GHz to 4.25 GHz, which agrees pretty well with the simulated results. Distributions of surface current, electromagnetic field and power loss density for the designed MMA are systematically investigated to explain microwave attenuation characteristic and loss mechanisms. More importantly, the prepared sample exhibits an optical transparency above 68% in the whole visible band, thus realizing a wide range of applications, such as optically transparent S-band absorbers.

The design of a 22 KHz 358 nW CMOS relaxation oscillator with a process and temperature compensation scheme is presented. Instead of the commonly used RC time constant, the oscillation period of the proposed circuit is determined by the resistance ratio of several resistors, which is insensitive to process and temperature variations. The on-chip relaxation oscillator is simulated in a 0.18 $\mu$m CMOS process. Without any calibration or off-chip components, the frequency variation of the proposed oscillator is ±3.24% across $-20^{\circ }\mathrm{\text{C}}$ to 100${}^{\circ }$C temperature range and 5 different process corners. Compared to the conventional relaxation oscillator, the frequency variation of this circuit is reduced by 89%. The simulated temperature coefficient is 111 ppm/${}^{\circ }$C, and the frequency variation over the supply voltage from 1.2 V to 1.7 V is 2.1%/V. The typical power consumption of the proposed circuit is 358 nW.

The structural, optical and electrical properties of Mn-doped ZnO samples with different percentages of Mn synthesized using the hydrothermal method were studied. The structural properties were studied using X-ray diffraction (XRD). The XRD patterns analyzed via the Rietveld structure refinement method showed a typical wurtzite structure and no other impurity phases. The lattice parameters calculated for the Mn-doped ZnO from the XRD pattern were found to be slightly larger than those of the ZnO, which indicates the substitution of Mn into the ZnO lattice. Transmission electron microscopy (TEM) revealed the synthesis of ZnO nanobelts. The incorporation of Mn ions into the ZnO lattice was also confirmed by Fourier transform infrared spectroscopy and UV-spectroscopy. Results show that the increase in Mn concentration increases the gap energy. The study of the electrical properties shows two conduction phenomena. The variation of impedance, dielectric constant and dielectric loss tangent is also discussed.

The objective work of this paper is to transform the nonlinear space-time fraction Whitham–Broer–Kaup equation into ordinary differential equation by using the conformal fractional derivative, and find the exact solutions through the complete polynomial discriminant system. At the same time, we build the appropriate solution for the identified parameters to show the existence of the solution. In addition, we provide the 3D and 2D graphics to show that the solutions are real and effective.

The multiple subdivision graph of a graph $G$, denoted by $S^n(G)$, is the graph obtained by inserting $n$ paths of length 2 replacing every edge of $G$. When $n=1$, $S^1(G)=S(G)$ is the subdivision graph of $G$. Let $G_1$ be a graph with $n_1$ vertices and $m_1$ edges, $G_2$ be a graph with $n_2$ vertices and $m_2$ edges. The quasi-corona SG-vertex join $G_1△G_2$ of $G_1$ and $G_2$ is the graph obtained from $S(G_1)\cup G_1$ and $n_1$ copies of $G_2$ by joining every vertex of $G_1$ to every vertex of $G_2$, and multiple SG-vertex join $G_1\odot G_2$ is the graph obtained from $S^n(G_1)\cup G_1$ and $G_2$ by joining every vertex of $G_1$ to every vertex of $G_2$. In this paper, we calculate analytic expression of characteristic polynomial of adjacency matrix of the above two types of joins of graphs for the case of $G_1$ being a regular graph. Then we obtain their adjacency spectra for the case of $G_1$ and $G_2$ being regular graphs.

We study the band structure of the lattice-matched graphene/$h$-BN bilayer system in the most stable configuration. An effective way to individually manipulate the edge state by the boundary potentials is proposed. It is shown that the boundary potential can not only shift and deform the edge bands, but also modify the energy gap. We also explore the transport properties of graphene/$h$-BN under a magnetic field. The boundary potential can change the distribution of the edge states, resulting in an interesting evolution of the quantized conductance.

In this paper, we study Hall effects of the monolayer MoS₂ with Rashba and Ising spin-orbit coupling (SOC) under the application of a circularly polarized light. The Chern number and spin textures at high frequency regime are studied based on the Floquet theory. We found that the SOCs induced valley Hall effect. The sign of Chern numbers at high frequency regime can be reversed by engineering interplay between Ising SOC and light intensity. The system undergoes a topological phase transition from valley Hall state to anomalous Hall state. By analyzing the spin texture, we study the origin of the Hall effects.

In order to explore the influence of driver’s characteristics in complex traffic flow, experienced, inexperienced attribution and the perception headway of the driver are introduced. Concurrently, an extended car-following model is established. The linear stability of the extended model is derived based on the control theory method, and obtains the stability conditions. This work verifies the impact of driver characteristics on traffic flow stability based on the open boundary simulation environment. The research results show that inexperienced driver will reduce the stability of traffic flow on complex roads, while experienced driver will improve the stability of traffic flow. Compared with the driver’s negative perception headway error, the positive perception headway error can improve the stability of traffic flow. More specifically, an experienced driver is good at predicting the state of the preceding vehicle, while the driver’s positive perception headway error tends to narrow the safe headway, and achieve the stability of traffic flow.