MoS2/DLC composite films were prepared by a dual-target co-sputtering technique on silicon substrate. The composite films show a smooth surface with significantly reduced cracks and columnar structures. The crystal particles of the composite films became finer after using the composite, and the graphite-like structure carbon was incorporated into MoS2, which affected the crystallization and growth

Mathematical modeling plays an important role to better understand the disease dynamics and designing strategies to manage quickly spreading infectious diseases in lack of an effective vaccine or specific antivirals. During this period, forecasting is of utmost priority for health care planning and to combat COVID-19 pandemic. In this study, we proposed and extended classical SEIR compartment model

We believe high accuracy analytic function approach will no longer be useful in calculating the ground state energy of V(x)=x4-λx6 and similar Hamiltonians.

The design and fabrication of the micro-nanostructures on materials surface is a challenging technology which can modulate and control the selective broadband spectra radiation, and the light-matter interaction mechanism behind have become the main research direction of filters, absorbers, heat radiators and other devices. Due to its high carrier mobility and excellent optical properties, graphene

Short-time Fourier transform is utilized for the data processing of traditional point-frequency Brillouin optical time-domain reflectometry (BOTDR). This method can improve the measurement speed, but theoretically there is a contradiction between spatial resolution and frequency resolution. To avoid this contradiction, a joint algorithm of smooth pseudo Wigner-Ville distribution (SPWVD) and four-parameter

In recent years, metasurfaces have demonstrated a tremendous development potential and applicability in various fields as they have overcome the problems associated with traditional optical devices, including bulkiness and difficulties related to integration. The vortex beam can carry an unlimited amount of orbital angular momentum which can greatly increase the capacity of the communication system

In this paper, a polarization and angle-insensitive multi-band adjustable terahertz absorber is proposed and numerically investigated, which is composed of a kind of periodic array square graphene ring with a Jerusalem cross graphene sheet. The numerical results indicate that the peaks absorptivity reach 99.9%, 99.9%, and 98.5% at 2.02THz, 3.44 THz, and 7.58 THz, respectively. The three resonance frequencies

The present mathematical study discussed the two-dimensional slow flow of linear Phan Thien Tanner (LPTT) fluid by taking into account the permeable slit with slippage walls and reabsorption undergoes uniformly through slit walls. Mathematical modeling of the two-dimensional flow situation is carried out in Cartesian coordinates and as result, a system of nonlinear PDEs along with nonhomogeneous boundary

Malaria is an infectious disease which causes a global health problem. This paper aims to construct and analyze a malaria model with a seasonal factor and also apply optimal control variables in the form of insecticide, prevention, and treatment. The malaria model without seasonal factor has two equilibria, namely, the disease-free equilibrium (DFE) and the endemic equilibrium (EE). The existence and

In this article, Buckingham’s π-theorem is applied to model electrospinning and electrospraying to find the fiber or particle diameter as a function of Taylor’s cone height, solution’s electrical conductivity, viscosity, surface tension, operating flow rate, and electric field intensity. The derived expressions elucidate how the fiber or particles diameter varies as a function of the process parameters

The aim of this comment paper is to show that the paper (Pop et al., 2021) contains many serious errors.

The aim of this study is to provide the numerical outcomes of a nonlinear HIV infection system of latently infected CD4+ T cells exists in bioinformatics using Morlet wavelet (MW) artificial neural networks (ANNs) optimized initially with global search of genetic algorithms (GAs) hybridized for speedy local search of sequential quadratic programming (SQP), i.e., MW-ANN-GA-SQP. The design of an error

In this letter, an improved SIR (ISIR) model is proposed, to analyze the spread of COVID-19 during the time window 21/01/2020–08/02/2021. The parameters can be extracted from an inverse problem of the ISIR to assess the risk of COVID-19. This study identifies that the cure rate is 0.05 and the reproduction number is 0.4490 during the time interval. The prediction values demonstrates high similarity

This paper deals with a set of three partial differential equations involving time-fractional derivatives and nonlinear diffusion operators. This model helps us to understand the HIV spread and transmission into the patient. First, we prove the existence and uniqueness of weak solutions to the mathematical model. Then, the Galerkin finite element scheme is implemented to approximate the solution of

Coronavirus (COVID-19) outbreak from Wuhan, Hubei province in China and spread out all over the World. In this work, a new mathematical model is proposed. The model consists the system of ODEs. The developed model describes the transmission pathways by employing non constant transmission rates with respect to the conditions of environment and epidemiology. There are many mathematical models purposed

We introduce a new stochastic robust solver to solve several classes of nonlinear stochastic partial differential equations (NSPDEs). This solver presents the closed formula for the stochastic solutions. In this regard, this solver is developed to accurately present the complete wave structure of the NSPDEs. To verify this solver, an application is given. The acquired stochastic solutions may be applicable

In this paper, the sub-equation method is used to obtain new types of complex traveling wave solutions of the time-fractional Burgers-Fisher equation. In this work is to compare the exact complex traveling wave solutions of new types and the numerical solutions obtained by suitable transformations of Caputo and Conformable derivatives. Also, to discuss the advantages and disadvantages of those derivatives

A new susceptible-exposed-infected-asymptomatically infected-removed (SEIAR) model is developed to depict the COVID-19 transmission process, considering the latent period and asymptomatically infected. We verify the suppression effect of typical measures, cultivating human awareness, and reducing social contacts. As for social contacts, the feasible measures encompass cutting off social connections

In November 2019, the coronavirus disease outbreak began, caused by the novel severe acute respiratory syndrome coronavirus 2. In just over two months, the unprecedented rapid spread resulted in more than 10,000 confirmed cases worldwide. This study predicted the infectious spread of coronavirus disease in the contiguous United States using a convolutional autoencoder with long short-term memory and

In this article, we investigate the exact solitary wave solutions to the 3D fractional Wazwaz-Benjamin- Bona-Mahony (3D-FWBBM) equation in emerging shallow-water waves. Different kinds of solutions such as hyperbolic, trigonometric, Jacobi elliptic, and rational function including some special known solitary waves like shock, singular, combo shock-solitary wave, and multiple soliton solutions are achieved

In ultrasonic vibration-assisted coatings, the verification of the surface roughness formation induced by the internal waves and the investigation of the maximum roughness position play a very important role and significantly contribute to the development of coating technology and to the comprehension of the induced internal flows. Therefore, this study aimed to verify the roughness formation process

We report the effect of In on superparamagnetic CoInxFe2-xO4 (x = 0.00, 0.05, 0.10 and 0.15) nanoparticles (NPs) prepared through one step hydrothermal method. The trace of In ions in the matrix causes to change the structural and magnetic properties of CoFe2O4 which is confirmed by XRD and magnetic analyses. X-ray diffraction (XRD) investigation along with the infrared spectroscopy exposed the formation

In this paper, we derive new closed-form radial solutions for the following elliptic Liouville equation △ϕ+φ(x)eϕ=0inΩ⊂Rn, and its generalized equation △ϕ+φ(x)eϕ=f(x)inΩ⊂Rn, where △ is the Laplace operator, φ and f are smooth positive functions.

Complex systems require rigorous analysis using effective method, in order to handle and interpret their information. Spectrum produced from Fourier transform infrared (FTIR) instrument is an example of a complex system, due to their overlapped bands and interactions within the spectrum. Thus, chemometrics techniques are required to further analyze the data, in particular, chemometrics fuzzy autocatalytic

Several deadly epidemics that have recognized as serious problems all over the world in the last few decades. Lassa hemorrhagic fever, coronavirus, dengue fever, malaria, and HIV are well-known deadly diseases in humans. In this research, we analysed the dynamics of the canine distemper virus (CDV) and rabies epidemics in the red fox population of the northern region of Italy with the help of time-fractional

Shale pore structure is an important factor in shale adsorption and percolation. To better characterize the pore structure of shales, this paper selects 24 shale core samples for high-pressure mercury intrusion (HPMI) test, and fractal theory and multifractal theory are applied to analyze the pore structures of shale nanopores. The fractal dimensions using different fractal models and the multifractal

Microwave flexible dielectric materials offer a new set of attractive applications for modern devices as well as for metamaterial research and technology. In this article, metamaterials with double-negative characteristics fabricated on a novel flexible dielectric substrate are presented. These novel flexible microwave substrates were prepared from Mg-Zn ferrite powder. The proposed flexible metamaterials

A switchable multi-wavelength Brillouin-Raman fiber laser (MW-BRFL) is presented in this work. The MW-BRFL consists of a full-open linear cavity in which dispersion compensating fiber is employed as the gain medium for Brillouin and Raman amplification. The switching operation for single- and double-wavelength spacing MW-BRFL can be implemented by controlling Brillouin pump (BP) power distribution

The Boussinesq equation simulates weakly nonlinear and long wave approximation that can be used in water waves, coastal engineering, and numerical models for water wave simulation in harbors and shallow seas. In this article, the sine-Gordon expansion (SGE) approach and the generalized Kudryashov (GK) scheme are used to establish broad-spectral solutions including unknown parameters and typical analytical

Here we prove that the results obtained in the above paper are unrealistic.

The purpose of this comment paper is to show that the results of the paper (Cui, 2021) are incorrect.

In this research, we investigate an SVIR system with distributed delay. We first provide some preliminary results on the proprieties of the Volterra function and the well-posedness of the solution, also the existence of a global compact attractor denoted D. Then we determine the global behavior of the solution in detail, where it is characterized in two different cases in terms of the basic reproduction

During the covid-19 pandemic, a considerable amount of data travels fast worldwide on the net, mainly on the social media platform where people all over the world have constant and easy access to submit materials and posts. A considerable amount of shared news embeds misleading information which affects negatively the cognitive and psychological health of its readers. The present case study focuses

We theoretically demonstrated a switchable, as well as tuneable, asymmetric transmission and reflective polarization conversion device in terahertz region. The proposed dual-function device composed of vanadium dioxide (VO2) and Dirac semimetal (DSM) metamaterials (MMs). Switching is achieved by exploiting the dielectric-to-metal phase transition of VO2 board. On the one hand, the hybrid MMs structure

Smooth, continuous, and bead-free zinc oxide (ZnO)-loaded electrospun poly(vinyl alcohol) (PVA) nanofibers were fabricated using 8% and 10% PVA concentration in water. Scanning electron microscope images showed a significant change in fiber diameter upon the addition of ZnO powders. X-ray diffraction and Raman spectral analysis revealed the successful physical blending of ZnO in PVA. Through UV-vis

Dust grain surface potential in multi-ion plasmas having two negative ions within the context of kappa-distributed dusty plasma is studied analytically and numerically. The plasmas current equations Xe+-F--SF6- and Ar+-F--SF6- solved using the typical parameters of laboratory multi-ion plasmas and attained dust grain surface potential strongly depends on the plasma parameters for example kappa, density

With the aid of the binary Hirota polynomial scheme, the bilinear form of the generalized (3 + 1)-dimensional Kadomtsev-Petviashvili equation, is constructed. Then, several classes of rogue waves-type solutions to the generalized (3 + 1)-dimensional Kadomtsev-Petviashvili equation within the frame of the bilinear equation are found. Finally, M-soliton solution and N-soliton based on the frame of the

In the current article, we will apply the scaling invariance technique to find conservation laws (CLs) for the nonlinear Chiral Schrödinger equation (NLCSE) with variable coefficients and the (2+1)-dimensional Maccari system. In addition to the establishment of CLs for these models, we will also look for diverse forms of dromions (solitons) solutions in polynomial forms such as optical solitary and

This study reports the effect of different weight percentages of chitosan binders in the graphene electrode on the distribution or homogeneity and electrochemical behaviour. The homogeneity of the chitosan binder is characterized by microstructural and structural analysis. Cyclic voltammetry and galvanostatic charge-discharge are employed to investigate the electrochemical performance and life cycle

Because the Duffing equation is very sensitive to weak signals and noise immunity, the modified Duffing detection system is applied to detect the weak nonlinear signal in nonlinear ultrasonic experiment. Firstly, the Duffing equation is improved to construct detection models to detect the nonlinear ultrasonic signal wave mixing in experiment. Then, the maximum Lyapunov exponent of detection model with

Localized defect states of liquid surface waves in non-Bragg periodic structures are investigated experimentally and validated numerically using the finite element method. Two parameters are considered, one is the position of the defect along the full length of the structure and the other is the filling fraction achieved by calibrating the length of the structures as a factor of the periodic length

A pair of adjacent beating flagella can be synchronized via hydrodynamic interactions at low Reynolds numbers. Here, we investigate the factors that determine the relaxation time for elastohydrodynamic synchronization by using the phase reduction theory. The results show that the relaxation time is determined primarily by the natural frequency of a flagellum as well as the coupling intensity between

The novel Coronavirus infection disease is becoming more complex for the humans society by giving death and infected cases throughout the world. Due to this infection, many countries of the world suffers from great economic loss. The researchers around the world are very active to make a plan and policy for its early eradication. The government officials have taken full action for the eradication of

The aim of this research is to investigate the relationships between the counts of cases with Covid-19 and the deaths due to it in seven countries that are severely affected from this pandemic disease. First, the Pearson’s correlation is used to determine the relationships among these countries. Then, the factor analysis is applied to categorize these countries based on their relationships.

In this paper, while examining the factorical effects of COVID-19 on different layers of capital market and economy, we examine market efficiency during Corona virus pandemic, as well as correlation and relationship between capital market indicators and market efficiency with COVID-19 data in Iran. Hurst exponent is able to identify fractal dimensions of time series data in various capital market indices

This study reported the structural properties, stability, mechanical anisotropy properties (anisotropy in Poisson's ratio, the shear modulus, Young's modulus, and the universal elastic anisotropy index) and electronic properties (electronic band structure) of Si20-xGex, Ge20-xSnx, and Si20-xSnx alloy (x = 0, 4, 8, 12, 16, and 20) in the P41212 phase. The lattice parameters of semiconductor alloys in

A comprehensive study on an E-mode AlGaN/GaN MIS-HEMT with triple barrier layer is conducted by Silvaco TCAD software. The effect of geometric parameters of gate dielectric layer, including the length of both sides and the recessed depth, on the device is studied. The simulation results show that the optimized device can reach a high threshold voltage (from 1.24V to 2.06V), a large maximum drain current

The physical parameters are important factors affecting the bubble-collapse strength. In this paper, single factor analysis and multiple regression analysis are applied to study the relationship among the physical parameters and bubbles maximum dimensionless radius (Rmax). There is a very weak linear correlation between the density, viscosity, sound velocity, surface tension, saturated vapor pressure

The R parameter in the second term of SG expression is undefined. The units of R are kg/(s2 K m) so that all terms in the SG expression have kg/(s3 K m) units. Also, the true Bejan number form is presented.

Approximate solutions of Klein–Gordon equation are obtained for the modified Mobius squared potential using the Nikiforov-Uvarov (NU) method. The relativistic energy eigenvalues and corresponding wave functions are obtained. It is further shown that in the non-relativistic limit, the energy eigenvalues reduces to that of Schrodinger equation. The behavior of CO, NO and HCl molecules are investigated

In this paper, numerical solution of third order integro-differential equation with boundary conditions is given utilizing Haar collocation technique. Both nonlinear and linear integro-differential equations are solved using this method. The third order derivative is approximated using Haar functions in both nonlinear and linear integro-differential equations. Integration is used to obtain the expression

This paper studies the second extended Calogero-Bogoyavlenskii-Schiff (eCBS) equation in (2+1)–dimensions, which was proposed in the literature a short time ago. Firstly, Lie symmetries of the equation are derived and thereafter we use them to perform symmetry reductions. Using its translation symmetries, the eCBS equation is reduced to a fourth-order ordinary differential equation, which is then solved

The Lump, multi-wave, breather, interactional solutions and stability analysis for the general r-th dispersionless Dym equation are obtained by some fruitful transformations. This approach based on an hypothesis that includes a general quadratic polynomial function with some appropriate parameters. Also for finding multi-wave, breathers and interaction phenomena we use different assumptions that includes

In this paper, we interrogate the optical soliton solutions of three-dimensional fractional Wazwaz Benjamin Bona Mahony (WBBM) equation. With a new auxiliary equation scheme, we form the solitary wave solitons of the considered model. By using this methodology, the acquired solutions conduct a range of the new families. These new classes of solutions include bright, dark, dark-bright, dark singular

The analytical solutions of the integrable generalized (2+1)-dimensional nonlinear conformable Schrödinger (NLCS) system of equations was explored in this paper with the aid of three novel techniques which consist of (G′/G)-expansion method, generalized Riccati equation mapping method and the Kudryashov method in the conformable sense. We have discovered a new and more general variety of exact traveling

In this manuscript, we derive integrals of motion for general anharmonic oscillators with damping and power-law forcing. The model under investigation has time-dependent coefficients, and the determination of these physical quantities is carried out using Noether’s theorem. The solutions must satisfy appropriate analytical conditions for the proposed quantities to be true integrals of motion. In turn

Recent discoveries of carbon-sulfur-hydrogen (C-S-H) room temperature superconductor (287.7 K) and near room temperature in hydride-based materials under high pressure have opened up an interesting and new avenue in the field of superconductivity. One of the important parameters of a superconductor is the coherence length, ξ which is the variation in the density of superconducting phase. ξ can also