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Metamaterial sensors are widely used because of their rich resonance behaviors. However, due to the dependence on resonance properties, many metamaterial sensors are difficult to be applied in measurement of the stationary thermal properties of Xuan paper samples in a wide frequency range. Many important properties of Xuan paper samples are related to thermal resonance properties,. such as folding resistance, tensile strength, ink-run property, whiteness, dry heat and wet heat aging. Here, a metamaterial sensor with smooth transmission performance in the operating frequency band is designed and fabricated. In experiments, by increasing temperature, the time for the thermal response current of the Xuan paper samples to reach the peak value is significantly reduced, and the average peak value is increased. The heat conduction of the Xuan paper samples is increased and the thermal resistance is reduaced. When the thickness of the Xuan paper sample is gradually increased, the time required for the thermal response current to reach the peak value is gradually increased and the average peak value is decreased. When the concentration of alum gelatin solution applied on the surface of the Xuan paper sample is gradually increased, the corresponding thermal response current is enhanced, and the time required to reach the peak is significantly reduced. The results show that the metamaterial sensor can be used to measure the thermal properties of Xuan paper samples.

A balance in nature is maintained by the coexistence of multiple species through interspecific competition. The evolutionary dynamics of cyclic interactions contain interactions that represent different biological behaviors. Biological behavior is influenced by the external environment, which may affect the stability of ecosystems. We investigated the evolutionary dynamics of interspecific competition after a periodic change in the external environment affects species. We consider that when the periodic external environments affect mortality, interspecific cyclical competition may be more pronounced, and thus increase the probability of extinction of species. By performing Monte Carlo simulations, we observed that the evolutionary dynamics of interspecific cyclic competition have different responsivity when subjected to external periodic changes at different frequencies, and stochastic resonance phenomena occurred. We show that the influence of the periodic external environment and its frequency is one of the factors that determine whether ecosystems coexist stably.

This study investigates the effect of low-pressure plasma (LPP) processing of a graphite foil as the cathode of a paper-based fluidic Al-air battery. A 10-s plasma treated battery exhibited better discharge performance in terms of the current density, power density, and energy density compared with an untreated battery. Scanning electron microscopy, x-ray photoelectron spectroscopy, and water contact angle measurements were used to investigate the difference in the surface properties of the graphite foil before and after LPP modification. Further, linear sweep voltammetry, constant current discharge measurement, and electrochemical impedance spectroscopy analysis were used to demonstrate the enhancement in discharge performance.

Since people use chaos extensively for a wide range of applications in data encryption and secure communications, a new method for designing practical high-dimensional discrete hyperchaotic systems is proposed for the first time in this paper. This method controls the range of the Lyapunov exponents in reverse by adding control variables so that the range of the values of the Lyapunov exponents is controlled within a specified interval, which is more suitable for engineering applications. Then, it is mathematically proved that the method ensures that the orbits of chaotic systems are globally finite and their Lyapunov exponents are bounded. In addition, as a practical demonstration of the selective image encryption scheme based on target template matching introduced in this paper, a 6-D discrete hyperchaotic system was created, and the analysis of the simulation results verifies the applicability of the 6-D hyperchaotic system designed by the method presented in this paper in the field of image encryption.

The air-cooled battery thermal management system (BTMS) is a safe and cost-effective system to control the operating temperature of battery energy storage systems (BESSs) within a desirable range. Different from the design of the air supply flow field of most BESSs in previous studies, this study proposes a novel combined the cooling air duct and the battery pack calculation method to enhance the heat dissipation of the battery. Using computational fluid dynamics (CFD) models, potential problems with numerical calculations of cooling air duct and battery packs alone and coupled simulations of the two are investigated. The important factor influencing the uniformity of air supply is identified, and creative measures for improvement are proposed. The results in this paper indicate that the uniformity of the outlet air supply does not indicate that the temperature uniformity performance of the matrix battery meets the requirements due to the variation of the sub air duct outlet pressure, and the coupling simulation of the cooling air duct and the battery pack is an essential process for BESSs. With the improvements proposed in this paper, the standard deviation coefficient of velocity is reduced from 60.3% to 12.6%. Furthermore, the innovative improvement of placing the partition at the connecting duct can regulates the battery temperature between 298.58 K and 311.73 K and ensures a maximum temperature difference of only 4.22 K for a single battery. Ultimately, the power consumption of the cooling system can be reduced by 6.9%. The results of the paper provide a guide for uniform heat dissipation in BESSs.

Threshold quantum secret sharing is a cryptography technique for dividing and reconstructing secret information. The dealer shares a secret based on quantum mechanics principles, and a subset of participants cooperate to recover that secret. For example, in k , n quantum threshold scheme and n , n quantum threshold scheme, the former can only reconstruct the secret when at least k shares are collected. The latter requires all n shares to be collected to reconstruct the secret. However, in real scenarios, the priority of participant identities may vary. In order to meet the actual needs of participants with different rights, this paper proposes a w , ω , n quantum secret sharing (QSS) scheme. When the sum of participants’ weights w is greater than or equal to a threshold ω, they can cooperate to reconstruct the secret. In order to achieve this, this paper uses the entangled state of single particles and constructs a verifiable QSS scheme based on the Chinese remainder theorem. Significantly, in case of a dishonest participant, the dealer can delete the participant before recovering the secret to ensure the security of the communication. This scheme is more flexible than other threshold protocols. At the same time, it reduces the communication cost of the participants. In addition, security analysis shows that the scheme resists typical external and internal attacks.

The invisibility condition of cloak in the Electro-Quasi-Static (EQS) field under the arbitrary transient excitation is given in this paper. Firstly, because electric field with magnetoelectric effect ignored can be attributed to the EQS field which is the transient electric field. In this case, the analytical invisibility conditions of infinite length coaxial cylinders cloaks under arbitrary transient excitation are derived in the EQS field. Then, by the finite element method(FEM) simulation, the correctness of the analytical invisibility condition is verified. Besides, this paper also established the equivalent circuit model for the cloak in the EQS field by the resistance and capacitance network. At last, analytical invisibility conditions of the concentric spheres cloak are also given. By the invisibility conditions proposed in this paper, the cloak could achieve stealth under the transient electric field which will greatly enhance the performance of the cloak.

The function of the biological nervous system is related to its dynamics. This paper explored the dynamics effects of bias current composed on inertial neural system based with two neurons. The model affected by the bias current can induce a reduction in the number of equilibrium points, the number of coexistence attractors, as well as the disturbance of the symmetry of this model compared to the model in without bias current. In absence of bias current we report multistability of up to six different attractors, symmetry birth of chaos via period-bubbling cascades in are reported in the model. Coexistence of symmetry bursting oscillations, parallel branch, and hysteresis dynamic are also presented in the system. The presence of bias current control the symmetry of the model and generates complex phenomena among others, coexistence of five asymmetric attractors, coexistence of asymmetric bubble and asymmetric bursting oscillation. Equilibrium point and Hopf bifurcation are perform in the paper. Furthermore, control of multistability is used for future application in engineering. Security analyses indicates that the proposed image encryption scheme exhibits a good encryption performance and can withstand known attacks.

This paper presents a lossy compression method for noisy images. The main contributions in this paper are: improve the performance of noisy image compression algorithms by using partial differential equations (PDEs) as an image preprocessing filter and show that it is more advantageous to apply a restoration filter before compressing noise images. Method: The preprocessing filter is applied to the noisy image first. A comparing of the obtained outcomes with those in the scientific literature devoted to the restoration of noisy images is performed. The filtered image is then submitted to a compression algorithm. The compression algorithm employed is a hybrid of the following: DWT + SPIHT + HUFFMAN. Results: The simulation results demonstrate that the suggested technique is as efficient as approaches described in the scientific literature for picture compression and/or image restoration.

This paper studies a class of circuit network model with fractional n-V-structure, the model contains several independent resistance elements, so it is the topology of multiple network models. First, this paper calculates the equivalent resistance of n-V circuit network by constructing equivalent model, and gives two closed equivalent resistance analytic expressions. Additionally, the concept of negative resistance is put forward. A series of special results of equivalent resistance are discussed. Finally, the complex impedance characteristics of fractional n-V structure circuit networks are studied in detail by using variable substitution technique. The amplitude frequency characteristics and phase frequency characteristics of fractional n-V structure circuit network are revealed through Matlab drawing research.

Due to the superior properties of graphene and the application potential of surface plasmons, the research of graphene surface plasmons has become a hot research direction. Based on the surface plasmons of graphene, this paper has done some researches on the plasma induced transparency, absorption, and slow light effect. The main work and results of this paper are as follows: we have designed a graphene-based metamaterial structure that can realize a dual plasma induced transparency (PIT) effect. The specific structure is formed by the periodic arrangement of graphene bands (as bright mode) and band edge microchips (as bright mode). We use the finite-difference time-domain (FDTD) method to study the dual PIT effect from the aspect of numerical simulation, and then further study the phenomenon of this device from the theoretical fitting of the coupled mode theory (CMT). The CMT model explores the physical mechanism of dual PIT spectral line and obtains a good fitting result. By studying the formation mechanism of the dual PIT effect, we have found that the graphene band as a bright mode interacts with the band edge microchip as a dark mode, and then the dual PIT is formed by destructive interference of the bright and dark modes. In order to better external modulation, the structure only studies the modulation effect caused by the change of Fermi level affected by the external voltage of graphene. Moreover, we also have studied the slow light performance of this structure, and the slow light coefficient reached 0.236 picoseconds (ps). This proposed coupling system of dual PIT effect has important research significance in optical switches, optical loop, and slow light devices.

This paper proposes a novel chaotic DICOM image encryption algorithm based on pseudo-random polyline and rapid diffusion-scrambling. This paper proposes to preprocess the image twice in the encryption process to ensure that any type of image can be encrypted, including images with negative pixel values, which increases the practicability of the algorithm. Two pseudo-random polylines are generated to segment the image during the encryption process. The pseudo-random polylines are generated from the information of the plaintext image, which ensures that each image produces different pseudo-random polylines and increases the security of the algorithm. In the encryption process, rapid diffusion-scrambling is used to avoid the waste of extra space. And piecewise diffusion and non-adjacent matrix reading are adopted to make the encryption more unpredictable. The scheme is analyzed from the performance indicators such as pixel correlation and key space, and the results demonstrated strong security and performance of the algorithm.

In this paper, a new sinusoidal cascade chaotic map model is proposed, which constructs chaotic system by sinusoidal cascade of two identical 1D chaotic maps. This model can generate 1D chaotic system with wider parameter range and wider chaotic region. To verify its application in image encryption, a chaotic image encryption algorithm based on spiral traversal and finite field bidirectional diffusion is proposed. The pseudo-random sequences generated by three kinds of 1D chaotic maps improved by the sinusoidal cascade chaotic map model are used as the ciphers of the cryptosystem. Among them, SHA-256, SHA-512 and plain image are combined to generate the initial value of the system. The experimental results and security analysis show that the encryption algorithm designed in this paper can effectively resist exhaustive attack, differential attack, noise attack and so on, and the proposed model has superior performance in encryption speed and security.

Using the simplest but fundamental example, the problem of the infinite potential well, this paper makes an ideological attempt (supported by rigorous mathematical proofs) to approach the issue of {\guillemotleft}understanding{\guillemotright} the mechanism of quantum mechanics processes, despite the well-known examples of the EPR paradox type. The new exact solution of the Schr\"odinger equation is analyzed from the perspective of quantum mechanics in the phase space. It is the phase space, which has been extensively used recently in quantum computing, quantum informatics and communications, that is the bridge towards classical physics, where understanding of physical reality is still possible. In this paper, an interpretation of time-dependent processes of energy redistribution in a quantum system, probability waves, the temperature and entropy of a quantum system, and the transition to a time-independent {\guillemotleft}frozen state{\guillemotright} is obtained, which is understandable from the point of view of classical physics. The material of the paper clearly illustrates the solution of the problem from the standpoint of continuum mechanics, statistical physics and, of course, quantum mechanics in the phase space., Comment: 32 pages, 15 figures

Nickel-based alloy Inconel 718 is widely used in aircraft engine industry because of its good mechanical properties. Inconel 718 is a typical difficult-to-machine material and its price is relatively expensive. Therefore, accurate prediction of Inconel 718 machined surface roughness with small sample space can improve machining efficiency, optimize process parameters and reduce machining cost. In this paper, a method is proposed to characterize the influence of cutting parameters on roughness by stablishing the corresponding relationship between the proportional hyperparameters in the multivariate kernel function and the cutting speed, cutting deep, feed rate and the rake angle of the tool. A multi input single output (MISO) multivariate Gaussian process regression (GPR) surface roughness prediction model with cutting speed, cutting depth, feed rate and tool rake angle as input variables and surface roughness as output variables is established. The model can not only output the predicted value of surface roughness, but also give the reliability of the predicted value. Experimental results show that the proportional hyperparameter has an independent adjustment function, and the influence of the process parameters characterized by the proportional hyperparameter on the surface roughness is consistent with the experimental results. The experimental results show that the average relative error of MISO multivariate GPR surface roughness prediction model proposed in this paper is 1.5%, which can accurately predict the surface roughness in small sample space.

General optical detection devices rely on converting photons to electrons (current), and do not allow for direct recording of the phase due to the high oscillation frequency. As so, the missing phase can only be recovered from the intensity measurements. The emerging non-convex phase retrieval algorithm, represented by the Wirtinger Flow (WF) algorithm requires multiple-shot coded diffraction patterns (CDPs) for accurate recovery. To achieve the real-time acquisition for multiple CDPs, this paper proposes a 4f imaging system based on an electrically tunable lens (ETL), which can be used for real-time acquisition of multiple-shot CDPs, and can take the advantages of highspeed, high-resolution, extended depth-of-field, high-sensitivity and low-cost imaging. In this paper, the performance of 4f-ETL based imaging system for phase retrieval with multiple CDPs is compared under different iteration times, different object size, different numbers of masks and different noise levels. Numerical experiments demonstrate the effectiveness and superiority of our proposed ETL-based imaging system, and ETL allows variable-distance focusing of imaging and display systems without mechanical structures, which reduces the mechanical complexity and power consumption, improves acquisition speed.

22 pags., 3 apps., The purpose of this paper is to discuss a number of issues that crop up in the computation of Poisson brackets in field theories. This is specially important for the canonical approaches to quantization and, in particular, for loop quantum gravity. We illustrate the main points by working out several examples. Due attention is paid to relevant analytic issues that are unavoidable in order to properly understand how computations should be carried out. Although the functional spaces that we use throughout the paper will likely have to be modified in order to deal with specific physical theories such as general relativity, many of the points that we will raise will also be relevant in that context. The specific example of the mock holonomy-flux algebra will be considered in some detail and used to draw some conclusions regarding the loop quantum gravity formalism., This work has been supported by the grant PID2020-116567GB-C22 funded byMCIN/AEI/10.13039/ 501100011033. E J S Villaseñor is supported by the Madrid Government (Comunidad de Madrid-Spain) under the Multiannual Agreement with UC3M in the line of Excellence of University Professors(EPUC3M23), and in the context of the V PRICIT (Regional Programme of Research and Technological Innovation). Bogar Díaz acknowledges support from the CONEX-Plus programme funded by Universidad Carlos III de Madrid and the European Unionʼs Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 801538.

According to N-soliton solutions generated by the Hirota’s bilinear method, the resonant collisions among diverse solitary waves can be obtained when the phase shifts of involved solitary waves tend to infinity. Under this constraint, the resonant collisions among a lump and dark line solitons can be derived from that of a breather and dark line solitons by means of an ingenious limiting approach. This paper takes the 2 + 1 -dimensional asymmetrical Nizhnik-Novikov-Veselov equation as an example to introduce how to utilize this constraint to derive the resonant collisions among different solitary waves containing breather, lump and dark line solitons in detail. At the same time, the dynamic behaviors of the interacting waveforms are exhibited visually by some figures which include intriguing phenomena. And the characteristics and properties of these interacting waveforms are discussed. In terms of feasibility and practicability, the procedures of analysis in this paper can be exploited widely to study resonant collisions of different waveforms in other integrable systems. The results obtained would enhance the completeness of nonlinear localized wave theory.

The partial differential equations (PDEs) describe several phenomena in wide fields of engineering and physics. The purpose of this paper is to employ the reproducing kernel Hilbert space method (RKHSM) in obtaining effective numerical solutions to nonlinear PDEs, which are arising in acoustic problems for a fluid flow. In this paper, the RKHSM is used to construct numerical solutions for PDEs which are found in physical problems such as sediment waves in plasma, sediment transport in rivers, shock waves, electric signals’ transmission along a cable, acoustic problems for a fluid flow, vibrating membrane, and vibrating string. The RKHSM systematically produces analytic and approximate solutions in the form of series. The convergence analysis and error estimations are discussed to prove the applicability theoretically. Three applications are tested to show the performance and efficiency of the used method. Computational results indicated a good agreement between the exact and numerical solutions.

In this paper, a kind of tenfold photonic quasicrystals based on the Penrose puzzle theory with the application of multicircular ring scatterers (MCRSs) is presented. It is divided into four kinds of square supercells and employed in a square lattice to constitute the first-order (1st), second-order (2nd), third-order (3rd), and fourth-order (4th) tenfold quasicrystal structure photonic crystals (TFQCSPCs) accordingly. In an attempt to evaluate the dispersion maps and equifrequency contour (EFC) profiles of such long-range ordered but not really periodic TFQCSPCs, an enhanced plane wave expansion (PWE) method is adopted. The photonic crystals (PCs) discussed in this paper are first classified into two major categories, air hole and dielectric column types which will be referred to as type 1, type 2 respectively in the following. The varying features of photonic band gaps (PBGs) of TFQCSPCs are inquired about by changing the refractive index (n) of the relevant medium and the number of rings (H) of MCRSs under two broad prerequisites of type 1 and type 2 PCs. The results are also compared with the associated properties of PBGs of traditional square lattice PCs (TSLPCs) and traditional triangular lattice PCs (TTLPCs) which employ MCRSs. Then, the 1st and 2nd TFQCSPCs and TSLPCs are fabricated in the form of hollow air holes dug in the silicon plate, and the transformation of their PBGs and EFCs is researched when the width (W) and H of the ring are adjusted. The possibility of implementing the phenomenon of polarization-insensitive self-collimation (PISC) in TFQCSPCs and TSLPCs is explored by examining the smoothest EFCs in EFC mappings. Eventually, our work actualizes the PISC phenomenon at seven normalized frequency (NF) values of 0.074, 0.168, 0.170, 0.172, 0.265, 0.270, and 0.297, which fills the gap of the PISC phenomenon in the low-frequency domain.

Microwave joining is a non-conventional joining method that can be used to join bulk metals. Different types of joints such as butt-joint, lap joint, etc can be successfully joined with this novel green technique of joining. In this paper, a domestic microwave oven having a power output of 700W, frequency of 2.45 GHz, and capacity of 25L is used to weld the SS202-SS202 and SS304-SS304 bulk metals. To characterize the lap joints Vicker’s hardness test and SEM of the welded specimens are carried out. The experimental modal analysis is used to measure the experimental eigenvalues and eigenvectors of the welded lap joints. The finite element method has been used to develop the simulated finite element model of the microwave welded joints. The developed finite element model may be very beneficial to predict the dynamic characteristics of the welded structures. However, the finite element method is a numerical tool that gives approximate results. The finite element modeling of the structures depends upon various uncertain factors such as structural material properties, dimensions, boundary conditions, etc Due to these uncertainties in the simulated finite element model, there is always an error between the simulated and experimental observations. In this paper, a lap joint of bulk metals is fabricated by using microwave hybrid heating and a finite element model updating technique such as a direct updating algorithm is proposed to update its simulated finite element model. The objective is to update the simulated mass and the stiffness matrices of the microwave welded lap joint. The experimental modal analysis is used to measure the natural frequencies of the lap joint specimen experimentally. It is observed that the direct updating algorithm can successfully update the simulated finite element model of the welded joints and reduces the error between the simulated and experimental natural frequencies. It is found that the maximum error between the predicted and measured natural frequencies reduces to 0.56% by using the proposed algorithm for welded joints.

When a Brownian particle moves in a confined space, the boundaries of the confined space can form an entropic barrier and thus induce the classical entropic stochastic resonance (ESR) phenomenon. This paper introduces a dichotomous fluctuating potential into the classical ESR model and studies the dynamics and ESR phenomena of the confined particle. It is shown that the amplitude of each harmonic component of both the horizontal and vertical displacements of the confined particle appears in various types of ESR phenomena, such as single-peak ESR, double-peak ESR, or even multi-peak ESR. This multi-peak ESR phenomenon is caused when the different dynamical states of the confined particle (under the joint action of the energy and entropy potentials) reach the optimal equilibrium. The results of this paper will help to understand the mechanism of stochastic dynamics of particles in confined spaces.

In this paper, a new discrete memristive chaotic map with infinitely wide parameter range is designed. Firstly, a discrete memristor based on a triangular wave function is constructed. The memristor conforms to the definition of generalized memristor, and a new three-dimensional memristive chaotic map is designed based on it. Numerical simulations show that the map has complex dynamic behavior. An improved perturbation method is proposed to estimate the output sequence of the chaotic system. At the same time, it is proved mathematically that the new map can always be in chaotic or hyperchaotic state with infinitely wide parameter range under certain conditions. By observing the Lyapunov exponent spectrum and the phase diagram, it is found as the absolute value of the parameter increases, the output range and ergodicity of the new map are also enhanced. We demonstrate that the new map has an initial-boosting behavior that depends on the initial conditions of the memristor. By changing the initial values of the memristor, we can control the appearance of attractor at different locations without loss. At the same time, this paper analyzes the mechanism of the discrete memristive chaotic map generating initial-boosting behavior, puts forward a method to make ordinary chaotic maps easier to obtain this behavior. Finally, the DSP hardware platform is used to implement the new map, which proves the physical existence and realizability of the map.

A large number of images are generated and distributed in various fields every day. To protect the image information from being stolen during the network transmission, this paper proposes a multiple-image encryption algorithm based on genetic central dogma and three-dimensional (3D) bit planes. This paper simulates the genetic central dogma and defines the 3D bit planes. Firstly, k original images are transformed into 8-bit binary and converted into a 3D matrix; secondly, the 3D matrix is permutated by rotating the bit plane and performing permutation among the bit planes; thirdly, we encode the scrambled 3D matrix into DNA codes. The diffusion is realized by imitating the genetic central dogma and introducing RNA mutations; finally, the encrypted images are obtained by the RNA decoding operation. Experimental results and algorithm analyses indicate that the proposed algorithm has strong security and desirable performance.

In order to satisfy the requirements of high quality and security during image transmission and storage, this paper proposes an image lossless compression encryption algorithm based on 1D chaotic map and Set Partitioned Embedded block encoder (SPECK). Initially, this paper proposes a new 1D chaotic map, and applies the chaotic sequences generated by it to each stage of the compression encryption algorithm. In addition, according to the feature that the degree of energy concentration in the wavelet coefficient matrix gradually decreases from low frequency to high frequency, this paper proposes a wavelet coefficient encryption algorithm, which can balance security and compression performance. Furthermore, multiple encryption points are introduced in the SPECK encoding process, and a secure SPECK encoding algorithm is proposed. Finally, theoretical analysis and simulation results show that the proposed algorithm is close to the theoretical value in terms of information entropy, correlation coefficient, mean square error of reconstructed image and other related indicators. Therefore, the algorithm has high security and lossless compression performance.

This paper is a contribution to study the effectiveness of Rastall gravity (RG) by another mechanism of warm viscous inflation inspired by modified Chaplygin gas (MCG). The matter contents of our cosmos are taken to be standard scalar field (ϕ) and radiation within flat FRW geometry. We establish the current model using intermediate form of scale factor and calculate the analytic solution of inflaton, effective potential V(ϕ) necessary to inflate the Universe and entropy density S under slow-roll limit. The further work in this paper is restricted to high dissipative regime, taking constant and variable dissipative (Γ) and viscous coefficients (ξ). The evaluated exact solutions are the main source in developing the inflationary observable like scalar/tensor power spectra, scalar/tensor spectral indices, tensor to scalar ratio and running of scalar spectral index for our model. The model parameters as well as additional theory parameter λ are constrained to check the compatibility of RG with Planck 2018 data via  − n s and α s − n s trajectories. We conclude that RG along with modification of CG model can lead to significant changes in the early universe.

In this paper, a finite element model updating algorithm is proposed to enhance the accuracy of the simulated finite element model of a smart structure (collocated piezoelectric patches embedded on a cantilever beam). Piezoelectric patches are used to sense and control the excessive vibrations of the structures. Mostly, they are mounted on flexible structures to measure their response at different excitations. The finite element method can be used to model the beam embedded with collocated piezoelectric patches. The complete finite element formulation of the smart structure is briefly described in this paper. There are different types of uncertainties that may be present in the simulated finite element model of a smart structure such as uncertainty in the structural boundary conditions, in the material elastic properties, the dimensions of the structure, piezoelectric elastic and electric properties, and the location of the piezoelectric patches mounted on the structure. In the present analytical study, the above uncertainties present in the smart structure are reduced by using the direct updating algorithm. It is found that the direct updating method through updating the mass and the stiffness matrices of the smart structure successfully enhance the accuracy of the simulated finite element model of the beam embedded with PZT patches. The state-space method is used to predict the response in the frequency domain. The maximum percentage error in the simulated finite element model of the piezoelectric embedded beam structure due to its structural and the electrical property uncertainty is 10.36% and 23.52% respectively and that was completely removed by using the direct updating algorithm. The optimal location of the piezoelectric patches is also taken as uncertainty which is successfully updated by using the proposed direct updating algorithm. The maximum percentage error in the natural frequencies of the smart structure due to location uncertainty is 18.39% which was also completely removed. To validate the outcomes, a frequency response function (FRF) is plotted.

This paper presents the preparation and characterisation studies of UV sensing films with a simple mathematical model for quantifying the lower UV irradiation duration/doses. To observe any appreciable changes in any properties of Poly-vinyl alcohol (PVA) films with UV irradiation, it has to be treated for few hours/days together. However, the technique presented here is an ultrasensitive method in which, the quantum dots (QDs) reinforced PVA film has become sensitive to UV radiations even for few seconds of exposure. To achieve this, Mercaptopropionic acid (MPA) capped CdTe QDs with superior fluorescence spectral properties grown in water medium were dispersed in PVA matrix to prepare QD-Polymer nanocomposites. Such fluorescence enriched films were stored in room temperature in ordinary environmental conditions for four years to check the degradability and viability. The stability of fluorescence and electrical properties of QDs inside PVA matrix was remarkable in this test period and were retained by the films even after such long duration. After that they were treated with UV radiation with the interval of few seconds to check the exposure recording ability of such films. The results are very promising in terms of sensitivity and the recording ability. Using the least square linear fit method a mathematical model was developed which would be useful in UV exposure sensing for smaller duration. This study also helps the concerned industries who would prepare film sensors for UV exposure quantification (like Litmus paper for pH sensing).

In this paper, the thermal transport of bilayer graphene is revisited by the homogeneous nonequilibrium molecular dynamics (HNEMD) method realized in a graphics processing unit based molecular dynamics package, GPUMD. Our simulations are carried out in three-dimensional boxes. An optimized Teroff potential is used to describe C-C covalent bonds, and the inter-layer van der Waals interaction is described by the 12-6 Lennard-Jones potential. Since the HNEMD method is homogeneous without boundary scattering, we obtain more accurate results than previous nonequilibrium molecular dynamics studies. Through intensive simulations, the main findings of the paper are as follows. (1) We find an efficient simulation setting, yielding results which are in good agreement with the experimental data; (2) Although the increase of the system size and the extension of production period has a beneficial effect to obtain more convergent results, these lead to large discrepancy with the experimental data; (3) The thermal conductivity is reduced by the phonon scattering among graphene layers; (4) The spectral decomposition of thermal conductivity shows that the bilayer graphene retains the spectrum of its monolayer counterpart except for the increasing magnitudes; (5) The spectral phonon mean free path of bilayer graphene reveals the presence of a new phonon mode which may have a negative contribution to the thermal conductivity.

In order to ensure the security of the encryption result and increase the speed of the encryption algorithm as much as possible, this paper proposes an efficient color image encryption algorithm based on 2D Sine-Logistic-Gaussian coupled chaos(2D-SLG chaos) and multi-objective optimized S-box. Firstly, this paper designs a 2D-SLG chaos to balance the complexity and computational cost of chaotic behavior. Secondly, this paper uses multi-objective particle swarm optimization to optimize the initial S-box to obtain an S-box with higher and balanced performance to perform the substitution operation. Finally, this paper uses the layer blending method to enhance the mutual influence between layers and uses the idea of linear congruence to generate permutation sequences to perform row and column shift operations. Experimental results show that the proposed encryption algorithm has excellent performance in key space, statistical analysis, key sensitivity, adjacent pixel correlation, differential attack, select plaintext attack and other security tests, and has high robustness and fast encryption speed. Therefore, the algorithm can meet the requirements of reliability and efficiency while ensuring strong security.

A modulation-doped field-effect transistor (MODFET) has been investigated in this paper. It is also called HEMT (high electron mobility transistor). The proposed MODFET is made up of Al0.30Ga0.70N as supply layer and GaN as channel or buffer layer, in which floating metal is embedded. Its T-gate is recessed to obtain higher gm, which results in improved RF characteristics. T-gate is used to minimize the gate resistance which reduces the power consumption of the proposed HEMT. A floating metal having triple teeth (TT), which resembles a comb is developed in GaN channel/buffer layer between the gate and drain electrodes to improve the device performance without increasing the dimensions of the device. The transition or cutoff frequency (f T) of 125 GHz and unity power gain (also called) maximum oscillation) frequency (f MAX) of 530 GHz at V DS = 10 V with V GS = 0.4 V have been reported in this paper. Analysis of power consumption of the proposed FET such as power gain (A P), output power (P OUT), and power-added efficiency (PAE) have been analyzed at 10 GHz in continuous wave mode and V DS = 35 V have been analyzed. The value obtained for P OUT, A P, and PAE is 67.5 dBmW, 11.6 dB, and 24.6%, respectively. All the obtained results from the Silvaco TCAD software have been verified with the mathematical model.

Memristors are often utilized in circuit model analysis as one of the fundamental circuit components. In this paper, a five-dimensional conservative memristor chaotic system is built after the introduction of the memristor into a four-dimensional conservative chaotic system. The dynamic changes of the system are examined using phase diagram, bifurcation diagram, and the Lyapunov exponent spectrum. A line equilibrium point, symmetry and multi-stability are characteristics of the system, the phase trajectory can also produce shrinking and structure transformation behavior with the change of parameters. Furthermore, the system has initial offset boosting behaviors, conservative flows of it can be altered in position by changing two initial values, respectively. Most notably, we discover that the complexity of the system rises with the inclusion of memristor and again with the addition of fractional differential operators. It is shown that the complexity of chaotic systems may increase with the addition of memristors and fractional-order differential operators. At last, the NIST is used to test the randomness of the sequence, and the system’s physical realizability is confirmed by the DSP platform.

In this paper, we apply the Carath\'eodory's method of geometrothermodynamics to investigate the behavior of the main thermodynamic parameters associated with a Schwarzschild black hole surrounded by quintessence. The corresponding Pfaffian form is constructed by means of the Schwarzschild radius $r_s$, and the quintessential radius $r_{\gamma}$ as independent variables. This form is then used to characterize the thermodynamic manifold. The homogeneity of the system allows for the recognition of the empirical temperature and entropy, and thus, connects with the usual laws of thermodynamics. In particular, we show that the Helmholtz and Gibbs free energies lead to the same value for the Schwarzschild black hole, in the case of the vanishing cosmological term., Comment: 9 pages, 7 figures

In this paper we demonstrate the surface plasmon resonance of nanoparticles in a two-dimensional elastic system. We use the layer potential technique related to the elastic equations and make an asymptotic expansion of the disturbed elastic wave field about the size of nanoparticles. The principal term in the asymptotic expansion mentioned earlier is related to the Neumann-Poincáre operator in the elastic system. Finally, the surface plasmon resonance is investigated by the spectral properties of the Neumann-Poincáre operator.

In this paper, we proposed a new fractional two dimensional trigonometric combined discrete chaotic mapping (2D-TCDCM) and a fractional 2-D Kawakami map within Caputo-Hadamard fractional difference. We observed the dynamic behaviours of the proposed Caputo-Hadamard fractional maps, including fractal graph, maximum lyapunov exponent, phase trajectory and randomness test. We illustrate the advantage of using Caputo-Hadamard fractional difference. As a conclusion, we get the condition of the proposed fractional map to behave chaotically with physics background.

In this paper, we are concerned with the gauge equivalent structures for the integrable (2+1)-dimensional nonlocal nonlinear Schr\"{o}dinger (NLS) equations. Through constructing the gauge transformation, we prove that these (2+1)-dimensional nonlocal equations, both focusing and defocusing, are gauge equivalent to two types of coupled (2+1)-dimensional Heisenberg ferromagnet equations and two types of coupled (2+1)-dimensional modified Heisenberg ferromagnet equations. As an appropriate extension, we further illustrate that the nonlocal NLS equation is gauge equivalent to two types of coupled Heisenberg ferromagnet equations and two types of coupled modified Heisenberg ferromagnet equations, while its discrete version is gauge equivalent to two types of coupled discrete Heisenberg ferromagnet equations and two types of coupled discrete modified Heisenberg ferromagnet equations, respectively. From its invariance with the combined parity-reflection and time-reversal operators, we can observe that there exist significant differences and intimate connections between standard and nonlocal equations. On the other hand, by using the Darboux transformation and some limit techniques, two types of deformed soliton solutions, namely, the deformed exponential solitons and the deformed rational solitons for the (2+1)-dimensional nonlocal defocusing NLS equation are given explicitly. With no loss of generality, two deformed soliton interactions and their various degenerate cases are discussed and illustrated through some figures.

In the field of vacuum interrupting, an important research is to improve the erosion resistance properties of contacts. In this paper, a two-dimensional axisymmetric swirl model based on basic parameters has been proposed to describe the formation and development of cathode spots of micro-scale alloy and nano-scale alloy electrode in a vacuum arc. In this model, the peak ion density of the plasma cloud, the mean charge state in near-cathode region, the electron temperature, and the near-cathode voltage drop are adopted as external parameters. Ions and electrons originating from the plasma cloud, thermo-field (T-F) emission, vaporization of metal atoms, backing ions and back-diffused electrons are all taken into consideration. The morphology and temperature of cathode spots crater and the liquid metal velocity of pure copper electrode (Cu), copper-chromium (Cu-Cr) electrode and tungsten-copper (W-Cu) electrode under the conditions of micro-scale grains and nano-scale grains are compared, respectively. Simulation results show that the cathode spot crater of the Cu-Cr electrode is smaller than that of the pure copper electrode. Moreover, it can hold more current and inhibit the formation of new cathode spots nearby. Cathode spots appearing on tungsten grains are smaller in size and have a lower probability of forming liquid metal droplets than Cu-Cr electrodes. Contacts made of nano-scale grain alloys have stronger erosion resistance properties than that of micro-scale alloy contacts and can reduce the maximum temperature of the cathode. The simulation results are in good agreement with other researchers’ results.

In this paper, we explore the formation of asymmetric modulation instability spectrum in the metamaterials as a result of the joined effect of self-steepening and intra-pulse Raman scattering. In general, the modulation instability gain spectrum is symmetric about the zero perturbation frequency. Here we observe asymmetric modulation instability gain spectrum and the asymmetry depends on the sign of the refractive index of the medium. When the refractive index of the medium is negative the band with high modulation instability gain is observed at positive detuning frequency regime in contrast to the case of positive refractive index regime where the band with high modulation instability gain is present at a negative detuning frequency regime. This preponderance is attributed to the opposite directionality of phase velocity and energy flow in a negative index material. Our study provides additional ways to tune soliton and ultrashort pulses utilizing engineering freedom of metamaterials.

With the rapid development of semiconductor chip circuit integration and miniaturization, especially the high integration of microwave chips, it has become critical to realize the surface microwave field imaging for such chips. In this paper, a new method of microwave field imaging for chip surface is proposed based on scanning probe microscopy. We analyse the echo signal and extract the peak-to-peak values to characterize the microwave field intensity on the chip surface by building a theoretical model of the microwave signal coupling. Using a high-precision scanning stage based on a piezoelectric ceramic tube, we realize the imaging of microwave field. The experimental results show that the imaging method can complete the chip surface microwave field imaging, which is important to support the optimization of semiconductor chip manufacturing process, fault analysis and new material research, and promote the development and progress of the semiconductor industry.

Due to the polarization dependence, there are two kinds of off-Γ bound states in the continuum (BIC) modes (TM-like mode and TE-like mode) for C2 symmetric grating structure. Compared to symmetrical protection BIC, off-Γ BIC is more susceptible to environmental changes, resulting in high refractive index sensitivity. In this paper, the influence of grating structure parameters on refractive index sensitivity of off-Γ BICs is studied, and the responses of two BIC modes to environmental refractive index are summarized. The refractive index sensitivities of TM-like mode and TE-like mode have different responses to grating structure parameters. The maximum sensitivity and figure of merit (FOM) of TM-like mode are 476 nm/RIU and 15866 RIU-1, while these of TE-like mode are 720 nm/RIU and 1440 RIU-1 respectively. These conclusions provide insights for the assembly and research of grating optical sensors based on off-Γ BICs.

Phase change materials (PCMs) such as temperature sensitive materials have received considerable attention in the optics and THz regime because of the reversable switching of their electromagnetic properties. In this paper, wideband switchable absorbers based on vanadium dioxide (VO2) have been designed and simulated at the terahertz (THz) regime. The switching functionality is enabled by the phase change of the VO2 layer from a metal state to an insulator through the temperature transition. The phase change temperature is 68°C. The first designed absorber shows a wideband absorption spectrum (fractional bandwidth of 92.3%) with absorptivity above 90% in the metal state, where conductivity of the VO2 layer is 200000 S/m, whereas the absorptivity is less than 3% in the insulator state, when the conductivity of the VO2 reaches 200 S/m. An equivalent circuit model-based analysis is presented for metal state. Based on the results, the extinction ration is less than –11 dB with 0.9 modulation depth for a wide frequency range from 2.2 to 5.87 THz. This makes the proposed structure a suitable candidate for broadband modulation at THz frequencies. An ultra-broadband absorption spectrum is achieved in the second design utilizing the stacked structure of two VO2 layers in metal state, where each layer acts as a resonator. This absorber prototype offers more than 90% absorptivity within 1.2 – 6.1 THz corresponding to a relative bandwidth of 135%.

Propagation of dust density waves (DDW) is theoretically investigated in a collisional plasma in the presence of an external magnetic field. The magnetic field is kept constant in a direction perpendicular to the direction of streaming ions, which is an important requirement for the self-excitation of these waves. Standard stability analysis is done to predict the conditions under which ion-drift instability may drive the DDW unstable. It is found that a minimum dust density is required to excite the wave. There exists a lower cut-off value of ion streaming velocity for the excitation of DDW which may change with the applied magnetic field and neutral gas pressure. The wave is found to behave complexly with the applied magnetic field and gets damped beyond a critical value. The results of this paper may be helpful in understanding the behavior of low-frequency dust modes as well as the background plasma both in laboratory and astrophysical environments.

The growing processing load and decreasing technology node has augmented the need for single ended memory. Consequently, generating requirement for a single ended sense amplifier for ease of integration with single ended memory. Therefore, this paper presents a single bitline based latch type sense amplifier. It is designed at feature size of 32 nm and its performance is evaluated at 1 V supply, with the environment temperature at 27 ⁰C. It is analyzed for its output waveform, delay, variability tolerance, and area occupancy. The ON current for the proposed sense amplifier is 1.2 uA, while the OFF current is 10 nA. The ON current for proposed sense amplifier is is 0.18, 0.43, and 0.88 times higher than SA-2, SA-5, and SA-6 respectively. While, its OFF current is lowest with the exception of SA-3 at 9 nA. Also, the delay for the proposed sense amplifier is minimal at 0.77 ns in comparison to other topologies. The SA-1, SA-2, SA-5, and SA-6 are 3.9, 2.8, 3.7, and 0.3 times slower than SA-P, thereby deeming its operation faster than others. The reliability for the proposed circuit is evaluated using process corner analysis for all performance parameters.

Two important mathematical methods for addressing uncertainty in data processing are multigranulation rough set (MGRS) and fuzzy bipolar soft set (FBSS). This paper describes a certain kind of multigranulation rough set in the context of multiple soft binary relations. We first define the multigranulation roughness of fuzzy bipolar soft sets in the two universes. Moreover, a detailed study of structural properties has been conducted in order to explore this concept. The key characteristics of the traditional MGRS model are completely preserved in this new approach. Following that, we suggest two decision-making algorithms with respect to aftersets and foresets of the soft binary relations over dual universes. This approach appears to be better suited and more adaptable than other available methods, making it a favorable option for addressing decision-making problems. Finally, we provide a practical application of the suggested approach to a real-world problem.

This paper presents a blended ferron in a ferromagnetic cluster where the electric polarization and magnetization tailor the quasi-particle characteristics. The resulting quasi-particle has coupled acoustic-polaron and ferron characteristics. The constant competition between electric polarization and magnetization alters the effective mass thereby reducing the global inertia of the quasi-particle. The impurity significantly affects the environment, and the resulting defects in the polarization and magnetization are soliton-like. It was observed that any gain in electric polarization is conveyed by a drop in magnetization, where the hybridization of magnetization and polarization gives rise to a new quasi-particle concept: a blended ferron. The latter is manifested by the local deformation of the electric polarization and depletion of the magnetization in the cluster’s signature of magnetic reordering

In this paper, we propose an effective numerical method, based on the use of two-dimensional Shifted fractional-order Gegenbauer Multi-wavelets, for finding the approximate solutions of the time-fractional distributed order non-linear partial differential equations. The method is applied to solve fractional distributed order non-linear Klein-Gordon equation, numerically. We derive an exact formula for the Riemann–Liouville fractional integral operator for the Shifted fractional Gegenbauer Multi-wavelets. Applying function approximations obtained by this method turns the considered equation into a system of algebraic equations. Error estimation and convergence analysis of the method are also studied. Some numerical examples are included to show and check the effectiveness of the proposed method.

The main purpose of this paper is to examine the viable attributes of charged compact stellar objects with anisotropic matter configuration in the framework of $f(\mathcal{R},\mathbf{T}^{2})$ theory. For this purpose, we use Tolman V solution and consider a specific functional form of this modified theory to examine the geometry of compact stars. The values of unknown parameters are found by the smooth matching of interior (static spherical metric) and exterior (modified Reissner-Nordstrom metric) spacetimes. We investigate the behavior of effective matter variables, anisotropy, equation of state parameters and energy bounds in the interior of the charged stellar objects. The stability of the compact stars is examined by speed of sound and adiabatic index. We find that the considered stars are viable as well as stable with all the required conditions in this modified theory of gravity.

A decade ago, experimental observations indicated that the repulsion between particles contained within a vesicle is a factor that induces the transformation of the vesicle. Recently, such a deformation was investigated in detail by means of the numerical simulation, whereas the division of a vesicle has never been realized. Its physical mechanism is not clear. In the present paper, a division rule is thermodynamically studied using the free energy including repulsion between polystyrene spheres. The number of daughter vesicles is given as a function of the ratio of osmotic pressure to surface energy.

In recent years, the proportion of methane explosion accidents in coal mine production accidents is increasing. The important measure to avoid methane explosion accident is to do well in methane leakage detection. Some of the surface plasmon resonance (SPR) based photonic crystal fibers (PCFs) have been proposed to achieve the methane gas sensing. However, it is difficult to fill methane gas into the inner air holes in PCFs. In order to address this issue, a D-shaped PCF methane gas sensor based on SPR was proposed and investigated based on the finite element method in this paper. A side polished air hole in the D-shaped PCF was utilized as the substrates for depositing the gold film and methane gas sensitive film. The sensing area is in direct contact with the outside methane gas. Simulation results showed that the measurement sensitivity of methane gas reached 9.88 nm/% at the methane concentration of 0%–3.5% with a linearity of 99.8%. The influence of optical structure parameters on sensor performances were also discussed. The designed sensor is expected to be a candidate for methane gas leakage detection for its simplicity and feasibility.

Quantum measurements based on mutually unbiased bases, mutually unbiased measurements and general symmetric informationally complete positive operator valued measurements, which are commonly used in quantum information and quantum computation. In this paper, by a broad class of informationally complete symmetric measurements and correlation matrices, some separability criteria are proposed for different quantum systems that are more robust and comprehensive than the corresponding criteria previously introduced L M Lai, T Li, S M Fei, and Z X Wang, (2018 Quantum Inf. Process., 17, 314); J W Shang, A Asadian, and H J Zhu, (2018 Phys. Rev. A 98, 022309). Furthermore, we extend the separability criteria of tripartite quantum systems to many-body systems. The proposed entanglement criteria may further enrich the relationship between quantum entanglement and measurement.