International Journal of Modern Physics B

In this paper, several types of solitons such as dark soliton, bright soliton, periodic soliton, kink soliton and solitary waves in three-dimensional and two-dimensional contour plot have been derived for the generalized third-order nonlinear Schrödinger dynamical equations (NLSEs). The generalized third-order NLSE is a significant model ultra-short pulses in optical fibers. The computational work and outcomes achieved show the influence and efficiency of current method. Furthermore, we can solve many other higher-order NLSEs with the help of simple and effective technique.

This paper is concerned with the structural balance problem for complex dynamical network with the help of coupling effect related to the external stimulations. Consider a network with time-varying and value-weighted links, which can be regarded as a dynamic system. The link dynamic system is modeled as a Riccati matrix difference equation with the coupling matrix related to the external stimulations. By using the Kronecker product as an effective tool, a linear matrix inequality (LMI) approach is developed to derive a simple criterion for ensuring that the discrete link system asymptotically achieves structural balance, meanwhile, the external stimulations track a corresponding vector signal as well. Simulation examples are given to demonstrate the usefulness of the proposed control scheme in this paper.

We propose a novel bio-sensor structure composed of slot dual-micro-ring resonators and mono-layer graphene. Based on the electromagnetically induced transparency (EIT)-like phenomenon and the light-absorption characteristics of graphene, we present a theoretical analysis of transmission by using the coupled mode theory and Kubo formula. The results demonstrate the EIT-like spectrum with asymmetric line profile. The mode-field distributions of transmission spectrum are obtained from 3D simulations based on finite-difference time-domain (FDTD) method. Our bio-sensor exhibits theoretical sensitivity of 330 nm/RIU, a minimum detection limit of $3.6\times 10^{-4}$ RIU, the maximum extinction ratio of 4.4 dB, the quality factor of $1.288\times 10^3$ and a compact structure of $15\mu \mathrm{\text{m}}\times 10\mu \mathrm{\text{m}}$. Finally, the bio-sensor’s performance is simulated for glucose solution. Our proposed design provides a promising candidate for on-chip integration with other silicon photonic element.

The effect of intrinsic point defects on the electronic structure and absorption spectra of ZnO was investigated by first-principle calculation. Among the intrinsic point defects in ZnO, oxygen vacancies $({\mathrm{\text{V}}}_{\mathrm{\text{O}}})$ and interstitial zinc $({\mathrm{\text{Zn}}}_i)$ have the lower formation energy and the more stable structure under zinc(Zn)-rich condition, whereas zinc vacancies $({\mathrm{\text{V}}}_{\mathrm{\text{Zn}}})$ and interstitial oxygen $({\mathrm{\text{O}}}_i)$ have the lower formation energy and the more stable structure under oxygen(O)-rich condition. The band gap of ${\mathrm{\text{Zn}}}_{36}{\mathrm{\text{Zn}}}_i{\mathrm{\text{O}}}_{36}$ becomes narrow and the absorption spectrum has a redshift. In the visible region, the photo-excited electron transition of ${\mathrm{\text{Zn}}}_{36}{\mathrm{\text{O}}}_{35}$ is graded from the valence band top to the impurity level and then to the conduction band bottom, showing the redshift of absorption spectrum of ${\mathrm{\text{Zn}}}_{36}{\mathrm{\text{O}}}_{35}$ and explaining the reason of ${\mathrm{\text{V}}}_{\mathrm{\text{O}}}$ forming a deep impurity levels in ZnO. Moreover, the impurity energy level of ${\mathrm{\text{Zn}}}_{36}{\mathrm{\text{O}}}_{35}$ coincides with the Fermi level, indicating the significant trap effect and the slow recombination of electrons and holes, which are conducive to the design and preparation of novel ZnO photocatalysts. The band gap of ${\mathrm{\text{Zn}}}_{35}{\mathrm{\text{O}}}_{36}$ and ${\mathrm{\text{Zn}}}_{36}{\mathrm{\text{O}}}_i{\mathrm{\text{O}}}_{36}$ broadened and the absorption spectrum showed blueshift, explaining the different values of the ZnO band gap width.

In this paper, we propose a new type of smooth positon called novel rational positon. Similar to classic smooth positons, the modulus square of novel rational positons can also be decomposed. But there is a fundamental difference between classic smooth positons and novel rational positons in terms of algebraic structure and dynamical properties. Specific propositions and conclusions are given in Secs. $2$ and $3$. Further, these two types of smooth positons sitting on a periodic line wave background are derived for the first time. In addition, a new nonlinear superposition between these two types of smooth positions and a kink soliton is constructed.

In this paper, with the help of a computer package program, the auto-Bäcklund transformation method (aBTM) and the finite forward difference method are used for obtaining the wave solutions and the numeric and exact approximations to the FitzHugh–Nagumo (F-N) equation, respectively. We successfully obtain some wave solutions to this equation by using aBTM. We then employ the finite difference method (FDM) in approximating the exact and numerical solutions to this equation by taking one of the obtained wave solutions into consideration. We also present the comparison between exact and numeric approximations and support the comparison with a graphic plot. Moreover, the Fourier von-Neumann stability analysis is used in checking the stability of the numeric scheme. We also present the $L_2$ and $L_{\infty }$ error norms of the solutions to this equation.

The first-principles calculations are used to investigate the effects on mechanical and electronic properties of Ti-7333 alloy under the tension stress along [001], [100] and [110] directions. First, we study the structure and elastic properties of Ti-7333 alloy with 2, 16, 54 and 128 atoms, finding that the structural parameters of four models are comparative due to the approximate value of c/a and the elastic properties are also similar. Hence, we choose Ti-7333 alloy with 16 atoms to study the effects on mechanical and electronic properties under tension stress along [001], [100] and [110] directions. The changes of independent elastic constants, Debye temperature and anisotropic behavior under different tension stress along all the three directions can reflect that the tensile strength of Ti-7333 alloy may exist between $-1$ and $-1.2$ GPa and also find that it is easier to change the resistance to deformation of Ti-7333 alloy under the tension stress along [100] direction compared with [001] and [110] directions. What’s more, the calculated mechanical parameters show that the Ti-7333 alloy is brittle and the tendency of variations is small with the increase in tension stress. The effects on electronic properties including metallic and covalent properties are not obvious due to the approximate height of TDOS, pseudogap and charge density.

In order to solve the problem of strong penetration and difficult attenuation of low-frequency sound wave in traditional materials, several three-dimensional acoustic black hole superstructures are designed. First of all, multi-stage acoustic black holes are designed. It is found that their sound insulation coefficient is about 0.9 in the frequency range of 50–1600 Hz when the ration of the outlet tip diameter to the inlet diameter is $d/D=12/99=0.121$. Then, the acoustic black hole thin and light superstructure was designed by embedding many acoustic black hole units in an array on the 10 mm thick plate. The sound insulation coefficient of two samples embedded 81 or 144 acoustic black holes is above 0.96 in the frequency range of 50–1600 Hz. To facilitate processing and engineering applications, we designed acoustic black hole wedge-shaped plate superstructures, and found that the average sound insulation of these acoustic black hole superstructures is 30 dB in the frequency range of 50–1600 Hz. These superstructures will be widely used in anechoic rooms, factories and aviation.

The main aim of this paper is to investigate the various dimensional nonlinear Fokas and Breaking soliton equations via a powerful analytical method, namely, sine-Gordon expansion method. Many new solutions such as complex combined dark-bright soliton solutions, singular and hyperbolic functions are derived. Choosing the suitable values of these parameters, various novel simulations are also plotted. Such results explain the wave behavior of the governing models, physically.

In this paper, the effects of the electric and magnetic fields on the optical absorption of GaAs/AlGaAs quantum multirings were studied. Using the two-dimensional finite element method, energy eigenvalues and wavefunctions were calculated, and optical absorption was obtained by the density matrix approach. The result showed that optical absorption increases with increasing number and size of the rings.

In this paper, the electrohydrodynamic (EHD) printing method for the flexible electronics with nanosilver ink was studied. The effect of DC voltage and air pressure on the printed nanosilver line was experimentally researched on the printing system. The necessary working voltage was above 600 V DC voltage, and when the voltage reached 1100 V, the line width increased from $100\mu \mathrm{\text{m}}$ to $600\mu \mathrm{\text{m}}$. The air supply of $10\mu \mathrm{\text{L/min}}$ resulted an obviously larger width than that of $1\mu \mathrm{\text{L/min}}$, but the printing process was unstable on the $10\mu \mathrm{\text{L/min}}$ condition. The EHD printing was applied to realize nanosilver ink line ranged from $60\mu \mathrm{\text{m}}$ to $600\mu \mathrm{\text{m}}$ and a kind of antenna pattern for radio frequency identification devices (RFID) was fabricated. This kind of EHD printing method has the advantages of high flexibility and printing resolution and shows potential prospects in the field of flexible electronics.

Diamond etching of $〈100〉$ orientation is processed in chemical vapor deposition (CVD) chamber using H₂ as reactive gas. Etching process happens on diamond substrates using a variety of etch mask materials including copper and nickel. Scanning electron microscope (SEM) and atomic force microscope (AFM) show different kinds of diamond etching pattern of two mask materials. It is observed that the etching pit of copper is tetrahedron, while the etching pit of nickel is step structure. This indicates diverse etching mechanism of diamond etched by different metal. Observing the surface etching topography of diamond and analyzing the etching mechanism of different metal can help study the growth of diamond by CVD and controllable etching of diamond.

To clear the intermetallic Fe-N phases, how to effect the strength and magnetic features of iron nitrides thin films, the thermodynamic, mechanical and magnetic attributes of the Fe-N phases have been calculated at Perdew, Burke and Enzerhof (PBE) level. The results show that the ${\mathrm{\text{Fe}}}_2\mathrm{\text{N}}$ and ${\mathrm{\text{Fe}}}_3\mathrm{\text{N}}$ phases are more stable than the other considered Fe-N phases by the formation energies. ${\mathrm{\text{Fe}}}_8\mathrm{\text{N}}$ and ${\mathrm{\text{Fe}}}_{24}{\mathrm{\text{N}}}_{10}$ phases are metastable at 0 K, which can be further decomposed into other more stable phases with temperature decreasing, i.e., ${\mathrm{\text{Fe}}}_8\mathrm{\text{N}}\to {\mathrm{\text{Fe}}}_4{\mathrm{\text{N+Fe}}}_4$ and ${\mathrm{\text{Fe}}}_{24}{\mathrm{\text{N}}}_{10}\to 6{\mathrm{\text{Fe}}}_2{\mathrm{\text{N+4Fe}}}_3\mathrm{\text{N}}$. ${\mathrm{\text{Fe}}}_3\mathrm{\text{N}}$ is the only brittle phase, while ${\mathrm{\text{Fe}}}_8\mathrm{\text{N}}$ is the most ductile phase. The ${\mathrm{\text{Fe}}}_2\mathrm{\text{N}}$ possesses the highest thermal conductivity by Debye temperatures. The ${\mathrm{\text{Fe}}}_8\mathrm{\text{N}}$ possesses the highest anisotropic behavior by $A_B$, $A_G$ and $A_U$ values. The ${\mathrm{\text{Fe}}}_4\mathrm{\text{N}}$ and FeN phases possess higher average magnetic moments (MM) than their neighbors. The ${\mathrm{\text{Fe}}}_8\mathrm{\text{N}}$ has stronger ionic bond by Mülliken population analysis.

In this paper, a modified Hindmarsh–Rose neuron model is presented, which has a fractional-order threshold magnetic flux. The dynamics of the model is investigated by bifurcation diagrams and Lyapunov exponents in two cases of presence and absence of the external electromagnetic induction. Then the emergence of the spiral waves in the network of the proposed model is studied. To find the effects of different factors on the formation and destruction of spiral waves, the external current, the coupling strength and the external stimuli amplitude are varied. It is observed that all of these parameters have significant impacts on the spiral waves. Furthermore, the external electromagnetic induction influences the existence of spiral waves in specific external current values.