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Comm.n.cations in Theoretical Physics 2024年第11期76卷 161-174页

作者： K Thulasidharan n Sinthuja n Vishnu Priya m Senthilvelan Departm.n. of Physics Vellore Institute of TechnologyVellore-632014TamilnaduIndia Departm.n. of Physics Anna UniversityChennai-600025TamilnaduIndia Departm.n. of mathematics Indian Institute of ScienceBangalore 560012KarnatakaIndia Departm.n. of nonlinear Dynamics Bharathidasan UniversityTiruchirappalli-620024TamilnaduIndia

We introduce a novel neural network structure called strongly constrained theory-guided neural network(SCTgnn),to investigate the behaviour of the localized solutions of the generalized nonlinear Schr?dinger(nLS)*** equation comprises four physically significant nonlinear evolution equations,namely,the nLS,Hirota,Lakshm.n.n-Porsezian-Daniel and fifth-order nLS *** generalized nLS equation dem.n.trates nonlinear effects up to quintic order,indicating rich and complex dynamics in various fields of *** combining concepts from the physics-informed neural network and theory-guided neural network(Tgnn)models,the SCTgnn aims to enhance our understanding of complex phenom.n.,particularly within nonlinear systems that defy conventional *** begin,we employ the Tgnn method to predict the behaviour of localized waves,including solitons,rogue waves and breathers,within the generalized nLS *** then use the SCTgnn to predict the aforem.n.ioned localized solutions and calculate the mean square errors in both the SCTgnn and Tgnn in predicting these three localized *** findings reveal that both models excel in understanding complex behaviour and provide predictions across a wide variety of situations.

关键词： generalized nonlinear Schr?dinger equation soliton rogue waves breathers SCTgnn Tgnn

A parallel complex divider architecture based on DCD iterations for computing complex division in mVDR beamformer

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Journal of Systems Engineering and Electronics 2018年第6期29卷 1124-1135页

作者： KIDAV Jayaraj U SIVA m.n.ai n m PERUmAL m Pillai Karunya Institute of Technology and Sciences Coimbatore 641114India national Institute of Electronics and Information Technology Calicut 673601India

This paper presents a hardware architecture using mixed pipeline and parallel processing for complex division based on dichotomous coordinate descent(DCD) iterations. The objective of the proposed work is to achieve low-latency and resource optimized complex divider architecture in adaptive weight computation stage of m.n.mum variance distortionless response(mVDR)algorithm. In this work, computation of complex division is modeled as a 2×2 linear equation solution problem and the DCD algorithm allows linear systems of equations to be solved with high degree of computational efficiency. The operations in the existing DCD algorithm are suitably parallel pipelined and the perform.n.e is optimized to 2 clock cycles per iteration. To improve the degree of parallelism, a parallel column vector read architecture is *** proposed work is implem.n.ed on the field programmable gate array(FPGA) platform and the results are compared with state-of-art literature. It concludes that the proposed architecture is suitable for complex division in adaptive weight computation stage of mVDR beamformer. We dem.n.trate the perform.n.e of the proposed architecture for mVDR beamformer employed in medical ultrasound imaging applications.

关键词： m.n.mum variance distortionless response(mVDR) beamformer adaptive weight dichotomous coordinate descent(DCD) algorithm medical ultrasound imaging

Shear modulus and damping ratio of sand-granulated rubber mixtures

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Journal of Central South University 2015年第8期22卷 3159-3167页

作者： m.Ehsani n.Shariatmadari S.m.mirhosseini School of Civil Engineering Iran University of Science and Technology Departm.n. of Civil Engineering Amirkabir University of Technology

Recycled waste tires when mixed with soil can play an important role as lightweight materials in retaining walls and embankm.n.s, machine foundations and railroad track beds in seismic zones. Having high damping characteristic, rubbers can be used as either soil alternative or mixed with soil to reduce vibration when seismic loads are of great concern. Therefore, the objective of this work was to evaluate the dynamic properties of such mixtures prior to practical applications. To this reason, torsional resonant column and dynamic triaxial experim.n.s were carried out and the effect of the important parameters like rubber content and ratio of mean grain size of rubber solids versus soil solids(D50,r/D50,s) on dynamic response of mixtures in a range of low to high shearing strain amplitude from about 4×10-4% to 2.7% were investigated. Considering engineering applications, specim.n. were prepared almost at the maximum dry density and optimum moisture content to model a mixture layer above the ground water table and in low precipitation region. The results show that tire inclusion significantly reduces the shear modulus and increases the damping ratio of the mixtures. Also decrease in D50,r/D50,s causes the mixture to exhibit more rubber-like behavior. Finally, normalized shear modulus versus shearing strain amplitude curve was proposed for engineering practice.

关键词： sand-rubber mixture shear modulus damping ratio low to high shear strain amplitude cyclic triaxial test torsionalresonant column test granular rubber

Travel time prediction with viscoelastic traffic model

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Applied mathematics and mechanics(English Edition) 2018年第12期39卷 1769-1788页

作者： Yongliang ZHAnG m.n.SmIRnOVA A.I.BOGDAnOVA Zuojin ZHU n.n.SmIRnOV Faculty of Engineering Science University of Science and Technology of China Faculty of mechanics and mathematics Moscow M.V.Lomonosov State University Scientific Research Institute for System Analysis Russian Academy of Sciences

Travel time through a ring road with a total length of 80 km has been predicted by a viscoelastic traffic model(VEm), which is developed in analogous to the non-newtonian fluid flow. The VEm expresses a traffic pressure for the unfree flow case by space headway, ensuring that the pressure can be determ.n.d by the assumption that the relevant second critical sound speed is exactly equal to the disturbance propagation speed determ.n.d by the free flow speed and the braking distance measured by the average vehicular length. The VEm assumes that the sound speed for the free flow case depends on the traffic density in some specific aspects, which ensures that it is exactly identical to the free flow speed on an empty road. To make a comparison, the open navier-Stokes type model developed by Zhang(ZHAnG, H. m. Driver memory, traffic viscosity and a viscous vehicular traffic flow model. Transp. Res. Part B, 37, 27–41(2003)) is adopted to predict the travel time through the ring road for providing the counterpart *** the traffic free flow speed is 80 km/h, the braking distance is supposed to be 45 m,with the jam density uniquely determ.n.d by the average length of vehicles l ≈ 5.8 m. To avoid possible singular points in travel time prediction, a distinguishing period for time averaging is pre-assigned to be 7.5 m.n.tes. It is found that the travel time increases m.n.tonically with the initial traffic density on the ring road. Without ramp effects, for the ring road with the initial density less than the second critical density, the travel time can be simply predicted by using the equilibrium speed. However, this simpler approach is unavailable for scenarios over the second critical.

关键词： travel time viscoelastic modeling distinguishing period for time averaging spatial-temporal pattern traffic jam

Experim.n.al Study of Wave Attenuation in Trapezoidal Floating Breakwaters

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China Ocean Engineering 2019年第1期33卷 103-113页

作者： A.H.nikpour m.n.moghim m.A.Badri Departm.n. of Civil Engineering Isfahan University of Technology Research Institute for Subsea Science and Technology Isfahan University of Technology

A comprehensive experim.n.al study was carried out on the regular wave attenuation with a trapezoidal pontoontype floating breakwater(FB) in deep water. The functionalities of two simple FB geometries consist of a rectangle and a trapezoid with the slope of 60° were investigated under the wave attack. A two-dim.n.ional wave flume was used in the experim.n.; the incident, transmitted waves, mooring line forces and motion responses of the floating breakwaters were measured. Also the influence of the sea state conditions(incident wave height and wave period)and structural parameters(draught of the structure) were investigated using the trapezoidal FB. Our experim.n.al results indicated that the trapezoidal FB significantly reduced the wave transmission and mooring line force when compared with rectangular FBs. A new formula was developed in order to predict the value of the transmission coefficient in trapezoidal FBs with the slope of 60°. Experim.n.al data showed to be consistent with the results of the formula.

关键词： regular waves floating breakwater(FB) wave flume trapezoid mooring line force transmission

Reliability and variance-based sensitivity analysis of arch dams during construction and reservoir impoundm.n.

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Frontiers of Structural and Civil Engineering 2019年第3期13卷 526-541页

作者： m.Houshm.n. KHAnEGHAHI m.ALEmBAGHERI n.SOLTAnI Departm.n. of Civil Engineering Shahid Beheshti UniversityTehranIran Departm.n. of Civil and Environm.n.al Engineering Tarbiat Modares UniversityTehranIran

The static perform.n.e of arch dams during construction and reservoir impoundm.n. is assessed taking into account the effects of uncertainties presented in the model properties as well as the loading *** arch dam is chosen as the case study;it is modeled along with its rock foundation using the finite elem.n. method considering the stage *** previous studies concentrated on simplified models and approaches,comprehensive study of the arch dam model along with efficient and state-of-the-art uncertainty methods are incorporated in this *** reliability method is performed to assess the safety level and the sensitivity analyses for identifying critical input factors and their interaction effects on the response of the *** sensitivity analysis based on improved Latin hypercube sampling is employed in this study to indicate the influence of each random variable and their interaction on variance of the *** levels of model advancem.n. are considered for the dam foundation system:1)m.n.lithic dam without any joint founded on the homogeneous rock foundation,2)m.n.lithic dam founded on the inhomogeneous foundation including soft rock layers,3)jointed dam including the peripheral and contraction joints founded on the homogeneous foundation,and 4)jointed dam founded on the inhomogeneous *** each model,proper perform.n.e indices are defined through limit-state *** this m.n.er,the effects of input parameters in each perform.n.e level of the dam are *** outcome of this study is defining the importance of input factors in each stage and model based on the variance of the dam ***,the results of sampling are computed in order to assess the safety level of the dam in miscellaneous loading and modeling conditions.

关键词： concrete arch dams reliability randomness improved Latin hypercube sampling variance-based sensitivity analysis exceedance probability Sobol index

Supersonic Shock Wave with Landau Quantization in a Relativistic Degenerate Plasma

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Chinese Physics Letters 2020年第1期37卷 34-38页

作者： m.Kr.Deka A.n.Dev Departm.n. of Applied Sciences Gauhati UniversityGuwahati-781014AssamIndia Center for Applied mathematics and Computing Siksha O Anusandhan(Deemed to be University)Bh u baneswar-751030OdishaIndia

A three-dim.n.ional(3D)BurgersJ equation adopting perturbative methodology is derived to study the evolution of a shock wave with Landau quantized magnetic field in relativistic quantum *** characteristics of a shock wave in such a plasma under the influence of magnetic quantization,relativistic parameter and degenerate electron density are studied with assistance of steady state *** magnetic field has a noteworthy control,especially on the shock wave's amplitude in the lower range of the electron density,whereas the amplitude in the higher range of the electron density reduces *** rate of increase of shock wave potential is much higher(lower)with a magnetic Held in the lower(higher)range of electron *** the relativistic factor,the shock wave's amplitude increases significantly and the rate of increase is higher(lower)for lower(higher)electron *** combined effect of the increase of relativistic factor and the magnetic field on the strength of the shock wave,results in the highest value of the wave potential in the lower range of the degenerate electron density.

关键词： density. solution. relativistic

Low temperature thermolum.n.scence behaviour of Y_2O_3 nanoparticles

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Journal of Rare Earths 2019年第1期37卷 19-23,M0002页

作者： S.Delice m.Isik n.m.Gasanly Departm.n. of Physics Hitit University Departm.n. of Electrical and Electronics Engineering Atilim University Departm.n. of Physics Middle East Technical University Virtual International Scientific Research Centre Baku State University

Y_2O_3 nanoparticles were investigated using low temperature thermolum.n.scence (TL) experim.n.s. TL glow curve recorded at constant heating rate of 0.4 K/s exhibits seven peaks around 19, 62, 91,115,162,196 and 215 K. Activation energies and characteristics of traps responsible for observed curves were revealed under the light of results of initial rise analyses and T_(max)-T_(stop) experim.n.al methods. Analyses of TL curves obtained at different stopping temperatures resulted in presence of one quasi-continuously distributed trap with activation energies increasing from 18 to 24 meV and six single trapping centers at49, 117, 315, 409, 651 and 740 meV. Activation energies of all revealed centers were reported in the present paper. Structural characterization of Y_2O_3 nanoparticles was accomplished using X-ray diffraction and scanning electron microscopy measurem.n.s.

关键词： Y2O3 Lum.n.scence Thermolum.n.scence Defects Rare earths

Effect of non-uniform temperature gradient and magnetic field on onset of marangoni convection heated from below by a constant heat flux

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Applied mathematics and mechanics(English Edition) 2010年第7期31卷 797-804页

作者： S.P.m.ISA n.m.ARIFIn R.nAZAR m.n.SAAD Institute for mathematical Research Universiti Putra Malaysia School of mathematical Sciences Universiti Kebangsaan Malaysia

This paper investigates the effect of non-uniform temperature gradient and magnetic field on marangoni convection in a horizontal fluid layer heated from below and cooled from above with a constant heat flux. A linear stability analysis is performed. The influence of various parameters on the convection onset is analyzed. Six non-uniform basic temperature profiles are considered, and some general conclusions about their desta- bilizing effects are presented.

关键词： maxangoni convection non-uniform temperature magnetic field

Ion acoustic shock and periodic waves through Burgers equation in weakly and highly relativistic plasmas with nonextensivity

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Plasma Science and Technology 2017年第1期19卷 7-19页

作者： m G HAFEZ n C ROY m R TALUKDER m HOSSAIn ALI Departm.n. of of Applied mathematics University of Rajshahi Rajshahi-6205 Bangladesh Departm.n. of mathematics Chittagong University of Engineering and Technology Chittagong-4349Bangladesh Plasma Science and Technology Lab Department of Applied Physics and Electronic EngineeringUniversity of Rajshahi Rajshahi-6205 Bangladesh

A comparative study is carried out for the nonlinear propagation of ion acoustic shock waves both for the weakly and highly relativistic plasmas consisting of relativistic ions and qdistributed electrons and *** Burgers equation is derived to reveal the physical phenom.n. using the well known reductive perturbation *** integration of the Burgers equation is performed by the（G￠/G）-expansion *** effects of positron concentration,ion–electron temperature ratio,electron–positron temperature ratio,ion viscosity coefficient,relativistic stream.n. factor and the strength of the electron and positron nonextensivity on the nonlinear propagation of ion acoustic shock and periodic waves are presented graphically and the relevant physical explanations are provided.

关键词： electron-positron-ion plasmas ion acoustic shock and periodic waves weakly and highly relativistic effects Burgers equation