The second wave of a novel coronavirus in Italy has caused 247,369 new cases and 1782 deaths only in October 2020. This significantly alarming infectious disease controlling board to impose again mitigation measures for controlling the epidemic growth. In this paper, we estimate the latest COVID-19 reproduction number (R_0) and project the epidemic size for the future 45 days. The R_0 value has calculated

We utilize the fractional modified Riemann-Liouville derivative in the sense to develop careful arrangements of space-time fractional coupled Boussinesq equation which emerges in genuine applications, for instance, nonlinear framework waves iron sound waves in plasma and in vibrations in nonlinear string and space-time fractional-coupled Boussinesq Burger equation that emerges in the investigation

The polycrystalline manganite Pr0.55CaxSr0.45-xMnO3 (x = 0.00, 0.05, 0.1, and 0.2) has been prepared by the solid state reaction technique to investigate its crystal structure, magnetic, and magnetocaloric properties. Critical behaviour around PM-FM phase transition has also been analyzed through various methods including modified Arrott plots (MAP), and critical isotherm analysis of Pr0.55CaxSr0.45-xMnO3

In this work, we demonstrate a high-power single-frequency nanosecond fiber master oscillator power amplifier (MOPA) at 1 μm with near transform-limited narrow spectral linewidth. The seed laser pulses were shaped to triangle for the purpose of suppressing the linewidth broadening induced by self-phase modulation (SPM). A tapered Yb-doped active fiber was used to enhance the stimulated Brillouin scattering

This paper studies the global stability of a discrete-time delayed influenza model with two-strain and two vaccinations. We use nonstandard finite difference (NSFD) method to discretize the continuous-time influenza model. First we show that the solutions of the model are positive and bounded, then we calculate all possible steady states of the model. The model has four steady states; disease free

A porous nanotube network structure of carbon allotrope was designed, denoted as P4/mmm C96. Besides its structure similar to carbon nanotubes, the most interesting thing about P4/mmm C96 is that its band structure is metallic. The shear modulus G, Young’s modulus E, and bulk modulus B of P4/mmm C96 is 49.4 GPa, 128.6 GPa, and 107.8 GPa, respectively. Although the elastic modulus of P4/mmm C96 is low

The current manuscript deals with the fractional dynamical system of transmission along with co-infection of TB in the HIV community including ten classes. We study the necessary conditions for the existence and uniqueness of the solution of the considered system under the fractional operator known as Atangana-Baleanu in Caputo sense. By using fixed-point theory, the qualitative analysis of the result

Spectroscopic properties play a significant role during the design and development of novel luminescent materials. In this work, quantum cutting (QC) luminescent materials KYF4:Tb3+,Yb3+ phosphors were successfully synthesized by sol-gel method. The crystal structure, morphology, fluorescence spectra, and decay curves were investigated by X-ray diffractometer (XRD), scanning electron microscope (SEM)

Indium substituted BiFe1-xInxO3 (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6) ceramics were synthesised via solid reactions method. The samples’ microstructure, dielectric, electrical and magnetic properties were investigated by X-rays diffractions (XRD), scanning electron microscopy (SEM), dielectric analyser, electrometer and vibrating sample magnetometer (VSM). From XRD, pristine BFO sample exhibited

By the theory of localized waves and the vectorial solution of the Maxwell equation, we develop and explore the vector characteristics of the new square Hermite–Gaussian vortex pulsed beam possessing orbital angular momentum (OAM). To investigate the propagation performance of this new beam, the measurement probability model of OAM states for square Hermite–Gaussian vortex pulsed beam propagation through

The main idea of this paper is to search for all traveling wave solutions to an intrinsic fractional discrete nonlinear electrical transmission line, which plays a essential role in obtaining the new insights in nonlinear voltage dynamics. We first give a brief introduction how to transform the discrete system into a continuous one, which is described by a fractional-order partial differential equation

Higher-order temporal-dispersion partial differential equations have its capability to visualize the evolution of steeper-waves for shorter wave-length better than the higher-order KdV does. In this work, we study the physical-structure propagations of generalized fifth-order nonlinear equation involving time-dispersion term. This model is recently proposed by Wazwaz (Xu and Wazwaz, 2020) and is considered

We develop a mathematical model for the transmission and spread of infections caused by the severe acute respiratory syndrome coronavirus 2 (SAR-CoV-2) which causes the coronavirus disease 2019 (COVID-19), a disease that has since been classified, by the World Health Organization, as a global pandemic. We focus attention on virus transmissions in a closed population and hence use a compartmental epidemic

We consider a two-photon laser in a cascade configuration coupled to an ordinary vacuum reservoir via a partially transmitting mirror. The impacts of the dephasing and the phase fluctuation on the entanglement, two-mode squeezing, and the intensity of the intracavity radiation are studied at steady-state. It so happens that the initial atomic coherence is the cause for the quantum properties of the

We propose a numerical investigation of slow light rainbow trapping and releasing in a tapered photonic crystal waveguide which is formed by linearly modifying the structural parameters in low-symmetric photonic crystals. Through dispersion analysis and numerical simulations, the electromagnetic waves of different frequencies in a normalized bandwith of ~5% can be trapped at different positions, as

We experimentally demonstrate the phase control of the controlled-NOT using dressing field in a hot atomic ensemble. This is more convenient for modulating the controlled-NOT gate with various relative phases. Moreover, with the phase modulated by changing the angle between the probe field and the dressing field, the enhanced output signal can be switched to the suppressed state in this logic process

We computed the deep inelastic scattering (DIS) structure functions F2(x,Q2) and FL(x,Q2) in the framework of Gribov-Levin-Ryskin-Mueller-Qiu, Zhu-Ruan-Shen (GLR-MQ-ZRS) equation. Both x and Q2 evolutions of the structure functions are studied in the kinematic range of 10−6≤x≤10−2 and 5≤Q2≤100GeV2 respectively. we have suggested analytical solutions to the structure functions, our results are inspired

The universal formulae for λ(χreal, Eg, T) and λ(χreal, Eg, T)p of insulator having less impurities are experimentally proved, where λ(χreal, Eg, T) is the mean escape depth at Kelvin temperature T of secondary electrons emitted from insulators with band gap Eg and efficient electron affinity χreal, λ(χreal, Eg, T)p is the λ(χreal, Eg, T) due to electron-lattice interaction. Based on the mechanism

In this work, the structural and electronic properties of graphene/germanene heterobilayer is investigated by using density functional theory. We find that the graphene and germanene are bounded together mainly by weak van der Waal forces. This is supported by small interlayer binding energy of graphene/germanene heterobilayer. In the heterobilayer, the Dirac cone characteristics of both graphene and

This study investigated the difference between the stress–magnetism relationships of ferromagnetic materials under tension and compression. Experimental results showed that the magnetic induction intensity of the ferromagnetic materials increased and decreased linearly with the increasing tensile and compressive stress, respectively, and that the response to tensile stress was more severe. The microstructural

The Airy transform was first introduced for a Gaussian beam, and the output beam is an Airy beam. When the Gaussian beam is extended to the Gaussian beam with optical vortex, what kind of output beam will be achieved by executing the Airy transformation. Therefore, the experimental research on Airy transformation of a Gaussian beam with optical vortex is carried out, including the generation of Gaussian

High Q factor multiple Fano resonance excitation in all-dielectric metasurfaces has become an effective mode to design high performance optical devices. This paper proposed an all-dielectric metasurface, composed of silicon cuboid etched with two semicircular holes into a unit cell and periodically arranged on a silica substrate. Numerical results show that triple high Q factor Fano resonances, corresponding

This article investigates the motion of double nonlinear damped spring pendulums with 3DOF in which its pivot point moves in an elliptic trajectory. The controlling system of motion is derived applying the Lagrange's equations and solved asymptotically up to the third approximation utilizing the multiple scales technique. The arising resonance cases are categorized in view of the solvability conditions

This article obtains the optical solitons of the complex fractional Ginzburg–Landau equation by the hypothesis of traveling wave and generalized projective Riccati equation scheme. There are four conditions, Kerr law, parabolic law, power law and dual power law of nonlinearity associated with the model. The constraint conditions for the existence of these solutions have also been discussed. Moreover

In this article, some new traveling wave solutions to a (2+1)-dimensional version of the nonlinear Schrödinger equation are constructed through two analytical techniques. The main integration methods employed in this paper are the generalized exponential rational function method and the extended sinh–Gordon equation expansion method. These techniques enable us to integrate analytical solutions for

In this trying time for the world battling different variants of the COVID'19 pandemic, different intervention strategies are being taken by government, to limit the spread of infection. Closing educational institutes, stay at home orders, campaigns for emphasis on vaccination, usage of medical mask and frequently sanitizing hands, etc. are the endeavors made by the authorities to decrease the number

In this paper, the growth of dendrites and its effect on soft magnetic properties of Fe78Si13B9 alloy during solidification under the effect of 0.18 T oriented magnetic field are studied. It shows that the magnetic field has strong guiding and promoting effect on the growth of dendrites. The primary branches of the α-Fe (Si) phase dendrites grow in parallel along the vertical direction of the magnetic

In this paper, we propose and demonstrate a terahertz bandpass filter based on substrate integrated plasmonic waveguide (SIPW) using the standard 0.25-μm InP DHBT fabrication process. In this design, a Yagi-Uda antenna-like subwavelength array with effective asymptotic frequency reduction, is etched on the top metal layer of substrate integrated waveguide (SIW) to support a spoof surface plasmon polaritons

We manufactured a new series of borosilicate glass doped with Dy3+ ions using a glass-quenching technique. To achieve the unique luminescence properties of our prepared glass, rare earth (Dy2O3) was incorporated into the glass matrix. The photoluminescence spectrum revealed five intense emission bands allocated at wavelengths 483 nm, 575 nm, 665 nm, 712 nm, and 752 nm, attributed to the transition

Tuning the third-order nonlinear optical (NLO) properties of graphene (G) is of great significance in nonlinear optics. In this work, Cu2Se/reduced graphene oxide (RGO) composites with different Cu2Se contents were prepared via a solvothermal method. The structure and morphology indicated that the Cu2Se nanoparticles were uniformly dispersed on the surface of the graphene nanosheets. The NLO properties

AlGaN-based deep ultraviolet (DUV) light emitting diodes (LEDs) are irradiated by fast neutrons, with optical and electrical properties analyzed in detail. Significant enhancement of output power is observed under neutron irradiation fluences of 6.0 × 1012 and 1.5 × 1013 cm−2. However, the device exhibits performance degradation as the fluence increases to 1.0 × 1014 cm−2. As previous observations

Chalcogenide glass (ChG) has been fabricated into on-chip integrated waveguides owing to its high nonlinear refractive index. However, the systematic research of Ge-Sb-S glass shows that Ge25Sb10S65 glass has greater hardness and stronger resistance to laser damage than other component glasses considered in this study. Additionally, the high nonlinear refractive index of Ge25Sb10S65 glass makes it

A model for Chlamydia trachomatis (CT) and Gonorrhea codynamics, with optimal control analysis is studied and analyzed to assess the impact of targetted treatment for each of the diseases on their co-infections in a population. Analysis of the gonorrhea-only sub-model shows the existence of a stable disease free equilibrium (DFE) and a stable endemic equilibrium (EE) when the associated reproduction

The dusty plasma system (containing nonthermally distributed inertialess electron species, warm inertial ion species, and positively charged stationary dust species) is considered. The basic features of subsonic and supersonic modified-ion-acoustic solitary and shock waves formed in such a dusty plasma system have been investigated by the reductive perturbation method. It has been shown that positively

Twisted light beams, or optical vortices, have been used to drive the circular motion of microscopic particles in optical tweezers and have been shown to generate vortices in quantum gases. Recent studies have established that electric quadrupole interactions can mediate an orbital angular momentum exchange between twisted light and the electronic degrees of freedom of atoms. Here we consider a quadrupole

In this paper, we use the rotating elliptical Gaussian beams (REGBs) to impinge the surfaces coated with cross-anisotropic metasurfaces (CMs) to investigate the Goos–Hänchen (GH) and Imbert–Fedorov (IF) shifts. The effect of the CM coating on the reflection coefficient in this system is considered. In particular, we will show that the angle of incidence and the relative permittivity of the weakly absorbing

We propose and demonstrate analytically, within the framework of a hydrodynamic model, a novel and simpler variational approach to study the asymptotic behavior of a continuous wave (cw) laser beam propagating in a nonlinear nonlocal medium.

In this paper, we demonstrate a domain inversion crystal structure to study the cascaded three-wave mixing process in a two peak Stark-chirped rapid adiabatic passage. We have achieved efficient wavelength conversion, which can be performed in intuitive order and counterintuitive order. The requirement of crystal is reduced and the flexibility of structure design is improved. When the conversion wavelength

Revealing the quantum regime of photovoltaics is crucial to enhancing the internal quantum efficiency of a double quantum dots (DQDs) photocell housed in a cavity. In this study, the performance of a quantum photovoltaic is evaluated based on the current–voltage and power-voltage characteristics in a cavity-coupled DQDs photocell. The results show that the cavity-DQDs coupling coefficient plays a dissipative

COVID-19 was declared a global pandemic by the World Health Organization in March 2020, and has infected more than 4 million people worldwide with over 300,000 deaths by early May 2020. Many researchers around the world incorporated various prediction techniques such as Susceptible–Infected–Recovered model, Susceptible–Exposed–Infected–Recovered model, and Auto Regressive Integrated Moving Average

In this work, we analyze the spreading of Covid-19 in Mexico using the spatial SEIRD epidemiologic model. We use the information of the 32 regions (states) that conform the country, such as population density, verified infected cases, and deaths in each state. We extend the SEIRD compartmental epidemiologic with diffusion mechanisms in the exposed and susceptible populations. We use the Fickian law

In this article, we develop a smoking model while considering some important features related to smoking habit like relapse and harmonic mean type incidence rate. The model is developed by using the existing literature and some key and updated research in the field. Besides proving of basic properties related to the model, we prove that the model has a smoking-free equilibrium which is locally and

Super-resolution imaging has been separately realized with two-dimensional photonic and phononic quasi-crystal flat lenses for the past few decades, but they are still utilized for independent disciplines. In this paper, Stampfli-type photonic quasi-crystal (S-PTQC) and S-PTQC flat lens are proposed. The numerical results demonstrate that the common photonic and phononic band gaps exist within two

A new extended direct algebraic method is applied to extract new traveling wave solutions for non-linear directional couplers with the optical meta-materials. This model studies light distribution from the main fiber into other branch fibers, which can be one or more than one. So, for this reason, twin couplers and multiple core couplers are studied in this paper. Further two cases in multiple core

A single bright highly dispersive optical soliton solution is recovered from semi–inverse variational principle. The model contains six power law nonlinear terms that constitute self–phase modulation effect which was proposed by Kudryashov. The amplitude–width relation of the soliton was finally recovered by Cardano’s approach with appropriate and necessary constraints that are presented.

We experimentally studied the formation of vacancy clusters and oxygen related defects in uranium oxide (UOx) thin films (<70 nm) changing the stoichiometry in the x = 2.2–3.5 range. Films were deposited on Si(0 0 1) by DC magnetron sputtering varying the substrate temperature (room temperature, 400 °C and 600 °C) and different relative O2 partial pressures in the argon-oxygen mixture. The different

Metastable liquid mixtures of parahydrogen and orthodeuterium are studied theoretically by means of computer simulations. No reduced propensity of the mixture to undergo crystallization is observed, compared to that of pure liquid parahydrogen. Demixing of the two species as a precursor of crystallization is not observed either.

In this work, it is reported that the interference pattern produced by an interferometer can be studied on the s-plane and its modulated function having three poles and two zeros over the imaginary axis. This is corroborated theoretically and experimentally using the interference pattern produced by a Fabry- Pérot interferometer based on Bragg gratings printed on the core of an optical fiber. From

A tunable dual-band metamaterial absorber composed of a gold square ring and a metal film separated by a strontium titanate dielectric is investigated. Two resonance peaks at frequencies 0.162 THz and 0.329 THz with over 99% absorbance are realized at room temperature. The maximum ratio between the lattice constant and the resonance wavelength is approximately 8.2%, which is much smaller than that

Static perfect fluid spaces are of great interest in metric theories of gravitation, they being used in building realistic models of some compact objects, like neutron stars and white dwarfs. In this article, we show that a compact static perfect fluid space with non-trivial solution f and Ricci curvature in the direction of the vector field gradf bounded below by a certain lower bound, is necessarily

We theoretically study the spatial focusing of surface polaritons (SPs) in a negative index metamaterial-atomic gas interface waveguide system, based on cross phase modulation (XPM) in a tripod type double electromagnetically induced transparency (EIT) scheme. In the linear region, we realize the low-loss stable propagation of SPs, and the group velocities of the probe and signal fields are well matched

This paper presents two HIV/HTLV co-infection models with antibody immune response. The first model is given by 5-dimensional ODEs that describe the within–host interactions of five compartments, susceptible CD4+T cells, HIV-infected cells, HTLV-infected cells, free HIV particles and HIV-specific antibodies. In the second model, we incorporate both silent HIV-infected cells and silent HTLV-infected

Terahertz waves have long been considered as the most efficient of many solutions to solve the blackout problem for the reason that terahertz waves have much stronger penetration than microwaves. In this paper, we will raise the incident wave band to terahertz band to discuss the application of terahertz technology in solving blackout problem. The plasma sheath attached to the reentry is considered

Dual-color upconversion luminescence of Er3+-doped (0.1% mol) lithium-niobate-on-insulator (Er:LNOI) on-chip ridge waveguides is observed under the excitation of a continuous-wave 980-nm semiconductor laser, emitting both blue (at 450 nm) and green (at 528.3 nm) fluorescence emissions. The on-chip waveguides, with a propagation loss of around 3 dB/cm at 1550 nm, are fabricated by diamond blade dicing

Random lasing emission was investigated from different ZnO nanostructures: a transition from nanowalls to nanoflakes; prepared on seeded glass substrate using simple chemical bath deposition method. The transition geometry of ZnO nanostructures were achieved simply by tuning the equimolar concentration of the chemical bath solution, zinc nitrate hexahydrate, and hexamethylenetetramine from 0.15 M,

In this paper, we investigate a diverse collection of exact solutions to a version of nonlinear Schrödinger equation with Kerr law nonlinearity. These results are obtained for the equation using the generalized exponential rational function method. The graphical interpretation of the solutions is also included to demonstrate the dynamic characteristics of the achieved results. It is found that the

The nonlinear Riemann wave equations (RWEs) and the Landau-Ginsburg-Higgs (LGH) equation are related to plasma electrostatic waves, ion-cyclotron wave electrostatic potential, superconductivity, and drift coherent ion-cyclotron waves in centrifugally inhomogeneous plasma. In this article, the interactions between the maximum order linear and nonlinear factors are balanced to compute realistic soliton