期刊文献+
共找到35篇文章
< 1 2 >
每页显示 20 50 100
The Similarity Transformation of Regularizing Functionals and Simularity Property of Their Fourier Transformations
1
作者 祝同江 《Journal of Beijing Institute of Technology》 EI CAS 1995年第2期105+99-105,共8页
Let and denote respectively the functionswhere λ≥1, The author discusses the similarity transformation of the regularizing functionals of these functions and the similar property of their Fourier transformation.
关键词 Fourier transform generalized functions/similarity transformation regularizing functionals
下载PDF
SIMILARITY TRANSFORMATION, THE STRUCTURE OF THE TRAVELING WAVES SOLUTION AND THE EXISTENCE OF A GLOBAL SMOOTH SOLUTION TO GENERALIZED KURAMOTO SIVASHINSKY TYPE EQUATIONS
2
作者 郭柏灵 潘兴德 《Acta Mathematica Scientia》 SCIE CSCD 1991年第1期48-55,共8页
The existence of a global smooth solution for the initial value problem of generalized Kuramoto-Sivashinsky type equations have been obtained. Similarty siolutions and the structure of the traveling waves solution for... The existence of a global smooth solution for the initial value problem of generalized Kuramoto-Sivashinsky type equations have been obtained. Similarty siolutions and the structure of the traveling waves solution for the generalized KS equations are discussed and analysed by using the qualitative theory of ODE and Lie's infinitesimal transformation respectively. 展开更多
关键词 similarity transformation THE STRUCTURE OF THE TRAVELING WAVES SOLUTION AND THE EXISTENCE OF A GLOBAL SMOOTH SOLUTION TO GENERALIZED KURAMOTO SIVASHINSKY TYPE EQUATIONS
下载PDF
Gershgorin and Rayleigh Bounds on the Eigenvalues of the Finite-Element Global Matrices via Optimal Similarity Transformations
3
作者 Isaac Fried Roberto Riganti Chen Yu 《Applied Mathematics》 2020年第9期922-941,共20页
The large finite element global stiffness matrix is an algebraic, discreet, even-order, differential operator of zero row sums. Direct application of the, practically convenient, readily applied, Gershgorin’s eigenva... The large finite element global stiffness matrix is an algebraic, discreet, even-order, differential operator of zero row sums. Direct application of the, practically convenient, readily applied, Gershgorin’s eigenvalue bounding theorem to this matrix inherently fails to foresee its positive definiteness, predictably, and routinely failing to produce a nontrivial lower bound on the least eigenvalue of this, theoretically assured to be positive definite, matrix. Considered here are practical methods for producing an optimal similarity transformation for the finite-elements global stiffness matrix, following which non trivial, realistic, lower bounds on the least eigenvalue can be located, then further improved. The technique is restricted here to the common case of a global stiffness matrix having only non-positive off-diagonal entries. For such a matrix application of the Gershgorin bounding method may be carried out by a mere matrix vector multiplication. 展开更多
关键词 Finite Elements Global Stiffness Matrix Gershgorin and Rayleigh Computed Upper and Lower Bounds on the Extremal Eigenvalues similarity transformations
下载PDF
Combined Method of Datum Transformation Between Different Coordinate Systems 被引量:4
4
作者 王晓妮 张洁 《Geo-Spatial Information Science》 2002年第4期5-9,共5页
The similarity transformation model between different coordinate systems is not accurate enough to describe the discrepancy of them.Therefore,the coordinate transformation from the coordinate frame with poor accuracy ... The similarity transformation model between different coordinate systems is not accurate enough to describe the discrepancy of them.Therefore,the coordinate transformation from the coordinate frame with poor accuracy to that with high accuracy cannot guarantee a high precision of transformation.In this paper,a combined method of similarity transformation and regressive approximating is presented.The local error accumulation and distortion are taken into consideration and the precision of coordinate system is improved by using the recommended method 展开更多
关键词 coordinate transformation similarity transformation regressive approximating
下载PDF
Similarity solutions of Prandtl mixing length modelled two dimensional turbulent boundary layer equations
5
作者 Bo-Hua Sun 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2022年第3期184-188,共5页
The exact similarity solutions of two dimensional laminar boundary layer were obtained by Blasius in 1908,however,for two dimensional turbulent boundary layers,no Blasius type similarity solutions(special exact soluti... The exact similarity solutions of two dimensional laminar boundary layer were obtained by Blasius in 1908,however,for two dimensional turbulent boundary layers,no Blasius type similarity solutions(special exact solutions)have ever been found.In the light of Blasius’pioneer works,we extend Blasius similarity transformation to the two dimensional turbulent boundary layers,and for a special case of flow modelled by Prandtl mixing-length,we successfully transform the two dimensional turbulent boundary layers partial differential equations into a single ordinary differential equation.The ordinary differential equation is numerically solved and some useful quantities are produced.For numerical calculations,a complete Maple code is provided. 展开更多
关键词 Turbulent boundary layers Laminar boundary layers similarity transformation similarity solution Prandtl mixing length Reynolds number
下载PDF
The Deformation Analysis of the 3D Alignment Control Network Based on the Multiple Congruence Models
6
作者 Xudong ZHANG Wenjun CHEN +5 位作者 Xiaodong ZHANG Yajun ZHENG Bin ZHANG Shaoming WANG Jiandong YUAN Guozhen SUN 《Journal of Geodesy and Geoinformation Science》 CSCD 2023年第2期21-31,共11页
In the construction and maintenance of particle accelerators,all the accelerator elements should be installed in the same coordinate system,only in this way could the devices in the actual world be consistent with the... In the construction and maintenance of particle accelerators,all the accelerator elements should be installed in the same coordinate system,only in this way could the devices in the actual world be consistent with the design drawings.However,with the occurrence of the movements of the reinforced concrete cover plates at short notice or building deformations in the long term,the control points upon the engineering structure will be displaced,and the fitness between the subnetwork and the global control network may be irresponsible.Therefore,it is necessary to evaluate the deformations of the 3D alignment control network.Different from the extant investigations,in this paper,to characterize the deformations of the control network,all of the congruent models between the points measured in different epochs have been identified,and the congruence model with the most control points is considered as the primary or fundamental model,the remaining models are recognized as the additional ones.Furthermore,the discrepancies between the primary S-transformation parameters and the additional S-transformation parameters can reflect the relative movements of the additional congruence models.Both the iterative GCT method and the iterative combinatorial theory are proposed to detect multiple congruence models in the control network.Considering the actual work of the alignment,it is essential to identify the competitive models in the monitoring network,which can provide us a hint that,even the fitness between the subnetwork and the global control network is good,there are still deformations which may be ignored.The numerical experiments show that the suggested approaches can describe the deformation of the 3D alignment control network roundly. 展开更多
关键词 similarity transformation 3D alignment control network deformation analysis hypothesis testing iterative global congruence test iterative combinatorial theory
下载PDF
Large Scale Fundamental Interactions in the Universe
7
作者 Qiao Bi 《Journal of Modern Physics》 2023年第S1期1703-1720,共18页
The author of this paper once attempted to propose a unified framework for gauge fields based on the mathematical and physical picture of the principal fiber bundle: that is, to believe that our universe may have more... The author of this paper once attempted to propose a unified framework for gauge fields based on the mathematical and physical picture of the principal fiber bundle: that is, to believe that our universe may have more fundamental interactions than the four, and these fundamental gauge fields are only components on the bottom manifold (i.e. our universe) projected by a unified gauge potential of the principal fiber bundle manifold;these components can satisfy the transformation of gauge potential, or even be transformed from one basic interaction gauge potential to another basic interaction gauge potential, and can be summarized into a unified equation, namely the generalized gauge equation expression, corresponding to gauge transformation invariance;so the invariance of gauge transformation is a necessary condition for unified field theory, and the four (or more) fundamental interaction fields of the universe are unified in a unified gauge field defined by the connection on the principal fiber bundle. In this paper, the author continues to propose a model of large-scale (gravitational) fundamental interactions in the universe based on the mathematical and physical picture of the principal fiber bundle, attempting to explain that dark matter and dark energy are merely reflections of these gravitational fundamental interactions that deviate in intensity from the gravitational fundamental interactions of the solar system at galaxy scales or some cosmic scales which are much larger than the solar system. All these “gravitational” fundamental interactions originate from the unified gauge field of the universe, namely the connection or curvature on the principal fiber bundle. These interactions are their projected representations on the bottom manifold (i.e. our universe) by different cross-sections (gauge transformations). These projection representations of the universe certainly are described by the generalized gauge equation or curvature similarity equation, and under the guidance of curvature gauge transformation factors, oscillate and evolve between the curvatures 1→0→-1→0→1 of the universe. 展开更多
关键词 Principal Bundle Gauge similarity transformation Dark Matter and Dark Energy Large-Scale Fundamental Interaction Evolution of Universe
下载PDF
Analytical solution of a double moving boundary problem for nonlinear flows in one-dimensional semi-infinite long porous media with low permeability 被引量:5
8
作者 Wen-Chao Liu Jun Yao Zhang-Xin Chen 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2014年第1期50-58,共9页
Based on Huang's accurate tri-sectional nonlin- ear kinematic equation (1997), a dimensionless simplified mathematical model for nonlinear flow in one-dimensional semi-infinite long porous media with low permeabili... Based on Huang's accurate tri-sectional nonlin- ear kinematic equation (1997), a dimensionless simplified mathematical model for nonlinear flow in one-dimensional semi-infinite long porous media with low permeability is presented for the case of a constant flow rate on the inner boundary. This model contains double moving boundaries, including an internal moving boundary and an external mov- ing boundary, which are different from the classical Stefan problem in heat conduction: The velocity of the external moving boundary is proportional to the second derivative of the unknown pressure function with respect to the distance parameter on this boundary. Through a similarity transfor- mation, the nonlinear partial differential equation (PDE) sys- tem is transformed into a linear PDE system. Then an ana- lytical solution is obtained for the dimensionless simplified mathematical model. This solution can be used for strictly checking the validity of numerical methods in solving such nonlinear mathematical models for flows in low-permeable porous media for petroleum engineering applications. Finally, through plotted comparison curves from the exact an- alytical solution, the sensitive effects of three characteristic parameters are discussed. It is concluded that with a decrease in the dimensionless critical pressure gradient, the sensi- tive effects of the dimensionless variable on the dimension- less pressure distribution and dimensionless pressure gradi- ent distribution become more serious; with an increase in the dimensionless pseudo threshold pressure gradient, the sensi- tive effects of the dimensionless variable become more serious; the dimensionless threshold pressure gradient (TPG) has a great effect on the external moving boundary but has little effect on the internal moving boundary. 展开更多
关键词 Threshold pressure gradient Moving boundary problem Fluid flow in porous media Low permeability similarity transformation Exact analytical solution
下载PDF
Exact Solutions of Klein-Gordon Equation with Scalar and Vector Rosen-Morse-Type Potentials 被引量:3
9
作者 A. Soylu O. Bayrak I. Boztosun 《Chinese Physics Letters》 SCIE CAS CSCD 2008年第8期2754-2757,共4页
We obtain an exact analytical solution of the Klein Gordon equation for the equal vector and scalar Rosen Morse and Eckart potentials as well as the parity-time (PT) symmetric version of the these potentials by usin... We obtain an exact analytical solution of the Klein Gordon equation for the equal vector and scalar Rosen Morse and Eckart potentials as well as the parity-time (PT) symmetric version of the these potentials by using the asymptotic iteration method. Although these PT symmetric potentials are non-Hermitian, the corresponding eigenvalues are real as a result of the PT symmetry. 展开更多
关键词 ASYMPTOTIC ITERATION METHOD NON-HERMITIAN HAMILTONIANS PT-SYMMETRIC POTENTIALS BOUND-STATES EIGENVALUE PROBLEMS DIRAC-EQUATION SCHRODINGER-EQUATION similarity transformation REAL PARTICLES
下载PDF
Casson fluid flow and heat transfer over a nonlinearly stretching surface 被引量:3
10
作者 Swati Mukhopadhyay 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第7期298-302,共5页
A boundary layer analysis is presented for non-Newtonian fluid flow and heat transfer over a nonlinearly stretching surface. The Casson fluid model is used to characterize the non-Newtonian fluid behavior. By using su... A boundary layer analysis is presented for non-Newtonian fluid flow and heat transfer over a nonlinearly stretching surface. The Casson fluid model is used to characterize the non-Newtonian fluid behavior. By using suitable transformations, the governing partial differential equations corresponding to the momentum and energy equations are converted into non-linear ordinary differential equations. Numerical solutions of these equations are obtained with the shooting method. The effect of increasing Casson parameter is to suppress the velocity field. However the temperature is enhanced with the increasing Casson parameter. 展开更多
关键词 nonlinear stretching Casson fluid heat transfer similarity transformations
下载PDF
Analytical solutions and rogue waves in (3+1)-dimensional nonlinear SchrSdinger equation 被引量:2
11
《Chinese Physics B》 SCIE EI CAS CSCD 2012年第3期138-144,共7页
Analytical solutions in terms of rational-like functions are presented for a (3+1)-dimensional nonlinear Schrodinger equation with time-varying coefficients and a harmonica potential using the similarity transforma... Analytical solutions in terms of rational-like functions are presented for a (3+1)-dimensional nonlinear Schrodinger equation with time-varying coefficients and a harmonica potential using the similarity transformation and a direct ansatz. Several free functions of time t are involved to generate abundant wave structures. Three types of elementary functions are chosen to exhibit the corresponding nonlinear rogue wave propagations. 展开更多
关键词 nonlinear SchrSdinger equation similarity transformation rational-like solution rogue wave
下载PDF
Spatiotemporal self-similar solutions for the nonautonomous (3+1)-dimensional cubic-quintic Gross-Pitaevskii equation 被引量:2
12
作者 戴朝卿 陈瑞品 王悦悦 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第3期145-150,共6页
With the help of similarity transformation, we obtain analytical spatiotemporal self-similar solutions of the nonautonomous (3+1)-dimensional cubic-quintic Gross-Pitaevskii equation with time-dependent diffraction,... With the help of similarity transformation, we obtain analytical spatiotemporal self-similar solutions of the nonautonomous (3+1)-dimensional cubic-quintic Gross-Pitaevskii equation with time-dependent diffraction, nonlinearity, harmonic potential and gain or loss when two constraints are satisfied. These constraints between the system parameters hint that self-similar solutions form and transmit stably without the distortion of shape based on the exact balance between the diffraction, nonlinearity and the gain/loss. Based on these analytical results, we investigate the dynamic behaviours in a periodic distributed amplification system. 展开更多
关键词 Gross-Pitaevskii equation similarity transformation self-similar solutions
下载PDF
Darcy-Forchheimer Hybrid Nano Fluid Flow with Mixed Convection Past an Inclined Cylinder 被引量:1
13
作者 M.Bilal Imran Khan +4 位作者 Taza Gul Asifa Tassaddiq Wajdi Alghamdi Safyan Mukhtar Poom Kumam 《Computers, Materials & Continua》 SCIE EI 2021年第2期2025-2039,共15页
This article aims to investigate the Darcy Forchhemier mixed convection flow of the hybrid nanofluid through an inclined extending cylinder.Two different nanoparticles such as carbon nanotubes(CNTs)and iron oxide Fe3O... This article aims to investigate the Darcy Forchhemier mixed convection flow of the hybrid nanofluid through an inclined extending cylinder.Two different nanoparticles such as carbon nanotubes(CNTs)and iron oxide Fe3O4 have been added to the base fluid in order to prepare a hybrid nanofluid.Nonlinear partial differential equations for momentum,energy and convective diffusion have been changed into dimensionless ordinary differential equations after using Von Karman approach.Homotopy analysis method(HAM),a powerful analytical approach has been used to find the solution to the given problem.The effects of the physical constraints on velocity,concentration and temperature profile have been drawn as well for discussion purpose.The numerical outcomes have been carried out for the drag force,heat transfer rate and diffusion rate etc.The Biot number of heat and mass transfer affects the fluid temperature whereas the Forchhemier parameter and the inclination angle decrease the velocity of the fluid flow.The results show that hybrid nanofluid is the best source of enhancing heat transfer and can be used for cooling purposes as well. 展开更多
关键词 Mixed convection similarity transformation HAM hybrid nanofluid CNTS Darcy Forchhemier inclined cylinder
下载PDF
Soliton excitations and interaction in alpha helical protein with interspine coupling in modified nonlinear Schrodinger equation 被引量:1
14
作者 Ming-Ming Li Cheng-Lai Hu +2 位作者 Jun Wu Xian-Jing Lai Yue-Yue Wang 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第12期130-135,共6页
The three-coupling modified nonlinear Schr?dinger(MNLS) equation with variable-coefficients is used to describe the dynamics of soliton in alpha helical protein. This MNLS equation with variable-coefficients is firstl... The three-coupling modified nonlinear Schr?dinger(MNLS) equation with variable-coefficients is used to describe the dynamics of soliton in alpha helical protein. This MNLS equation with variable-coefficients is firstly transformed to the MNLS equation with constant-coefficients by similarity transformation. And then the one-soliton and two-soliton solutions of the variable-coefficient-MNLS equation are obtained by solving the constant-coefficient-MNLS equation with Hirota method. The effects of different parameter conditions on the soliton solutions are discussed in detail. The interaction between two solitons is also discussed. Our results are helpful to understand the soliton dynamics in alpha helical protein. 展开更多
关键词 SOLITON three-coupling nonlinear modified Schrodinger equation similarity transformation
下载PDF
A New Procedure to Solve the Non-Linear Reaction-Diffusion Equation
15
作者 吴燕翔 王良恩 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2000年第1期92-94,共3页
1 INTRODUCTIONThe concentration distribution of reactant in porouscatalyst pellet not only is the basis of calculating theeffectiveness factor,but also has a great significancein investigating the reaction and mass tr... 1 INTRODUCTIONThe concentration distribution of reactant in porouscatalyst pellet not only is the basis of calculating theeffectiveness factor,but also has a great significancein investigating the reaction and mass transfer in thecatalyst pellet.In principle,the concentration distri-bution and the effectiveness factor of a catalyst pelletcan be obtained by solving the reaction-diffusion equation.However,most of the differential equations haveno analytical solution except for some simple cases.The previous investigators have made great efforts to calculate the effectiveness factors of catalysts.They first obtained asymptotic solutions of effective-ness factor in the cases of the Thiele modulus φ→Oand φ→oo by means of perturbation method,thensynthesized the information of the asymptotic solu- 展开更多
关键词 reaction-diffusion equation SOLUTION similarity transformation perturbation analysis effectiveness factor
下载PDF
MHD stagnation point flow of a micropolar fluid towards a heated surface
16
作者 M.ASHRAF M.M.ASHRAF 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2011年第1期45-54,共10页
The problem of two dimensional stagnation point flow of an electrically conducting micropolar fluid impinging normally on a heated surface in the presence of a uniform transverse magnetic field is analyzed. The govern... The problem of two dimensional stagnation point flow of an electrically conducting micropolar fluid impinging normally on a heated surface in the presence of a uniform transverse magnetic field is analyzed. The governing continuity, momentum, angular momentum, and heat equations together with the associated boundary conditions are reduced to dimensionless form using suitable similarity transformations. The reduced self similar non-linear equations are then solved numerically by an algorithm based on the finite difference discretization. The results are further refined by Richardson's extrapolation. The effects of the magnetic parameter, the micropolar parameters, and the Prandtl number on the flow and temperature fields are predicted in tabular and graphical forms to show the important features of the solution. The study shows that the velocity and thermal boundary layers become thinner as the magnetic parameter is increased. The micropolar fluids display more reduction in shear stress as well as heat transfer rate than that exhibited by Newtonian fluids, which is beneficial in the flow and thermal control of polymeric processing. 展开更多
关键词 magnetohydrodynamics (MHD) stagnation flow micropolar fluids finitedifferences similarity transformations boundary layer
下载PDF
Fractional Analysis of Viscous Fluid Flow with Heat and Mass Transfer Over a Flexible Rotating Disk
17
作者 Muhammad Shuaib Muhammad Bilal +1 位作者 Muhammad Altaf Khan Sharaf J.Malebary 《Computer Modeling in Engineering & Sciences》 SCIE EI 2020年第4期377-400,共24页
An unsteady viscous fluid flow with Dufour and Soret effect,which results in heat and mass transfer due to upward and downward motion of flexible rotating disk,has been studied.The upward or downward motion of non rot... An unsteady viscous fluid flow with Dufour and Soret effect,which results in heat and mass transfer due to upward and downward motion of flexible rotating disk,has been studied.The upward or downward motion of non rotating disk results in two dimensional flow,while the vertical action and rotation of the disk results in three dimensional flow.By using an appropriate transformation the governing equations are transformed into the system of ordinary differential equations.The system of ordinary differential equations is further converted into first order differential equation by selecting suitable variables.Then,we generalize the model by using the Caputo derivative.The numerical result for the fractional model is presented and validated with Runge Kutta order 4 method for classical case.The compared results are presented in Table and Figures.It is concluded that the fractional model is more realistic than that of classical one,because it simulates the fluid behavior at each fractional value rather than the integral values. 展开更多
关键词 Caputo derivatives similarity transformation RK4 soret effect Dufour effect
下载PDF
Hyperreflexivity of Operator Algebras of the Banach Space
18
作者 YUANGuo-chang QINLi-ming 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2005年第2期178-184,共7页
In this paper, we introduced the hyperreflexivity of operator algebra A on Banach space, discussed the necessary, and sufficient condition that A is hyperreflexive, the estimate of hyperreflexive constant and the inva... In this paper, we introduced the hyperreflexivity of operator algebra A on Banach space, discussed the necessary, and sufficient condition that A is hyperreflexive, the estimate of hyperreflexive constant and the invariance of hyperreflexivety under the similarity transformation. 展开更多
关键词 Banach space hyperreflexive operator algebra similarity transformation
下载PDF
Solitons for the cubic-quintic nonlinear Schrdinger equation with varying coefficients
19
作者 陈元明 马松华 马正义 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第5期133-139,共7页
In this paper,by means of similarity transfomations,we obtain explicit solutions to the cubic-quintic nonlinear Schr顜僤inger equation with varying coefficients,which involve four free functions of space.Four types of... In this paper,by means of similarity transfomations,we obtain explicit solutions to the cubic-quintic nonlinear Schr顜僤inger equation with varying coefficients,which involve four free functions of space.Four types of free functions are chosen to exhibit the corresponding nonlinear wave propagations. 展开更多
关键词 cubic-quintic nonlinear SchrSdinger equation similarity transformation explicit solu-tions
下载PDF
A Computational Investigation of the Lid-Driven Cavity Flow
20
作者 Nawal Odah Al-Atawi Daoud Suleiman Mashat 《American Journal of Computational Mathematics》 2022年第2期283-296,共14页
The lid-driven cavity is an important fluid mechanical system that serves as a benchmark for testing numerical methods and for studying fundamental aspects of incompressible flows in confined volumes. These flows are ... The lid-driven cavity is an important fluid mechanical system that serves as a benchmark for testing numerical methods and for studying fundamental aspects of incompressible flows in confined volumes. These flows are driven by the tangential motion of a bounding wall. The lid-driven cavity serves as a benchmark for testing numerical methods and for studying fundamental aspects of incompressible flows in confined volumes. This article presents a complete study of lid-driven cavity flows, with the primary focus being placed on the development of the flow when the Reynolds number was increased. In order to fully comprehend the physics of flow, it is necessary to take into consideration not only pure two-dimensional flows but also flows that are periodic in one space direction and the whole three-dimensional flow. 展开更多
关键词 STEADY Two Dimensional Navier Stokes similarity transformation Finite Difference Scheme
下载PDF
上一页 1 2 下一页 到第
使用帮助 返回顶部