Noether-Type Conserved Quantities on Time Scales for Birkhoffian Systems with Delayed Arguments

2021 ◽  
Author(s):  
Xiang-Hua Zhai ◽  
Yi Zhang
Keyword(s):  
Time Scales ◽  
Conserved Quantities ◽  
Delayed Arguments

scholarly journals Vartiational Optimal-Control Problems with Delayed Arguments on Time Scales

2009 ◽  
Vol 2009 ◽  
pp. 1-15 ◽  
Author(s):  
Thabet Abdeljawad (Maraaba) ◽  
Fahd Jarad ◽  
Dumitru Baleanu
Keyword(s):  
Optimal Control ◽  
Time Scales ◽  
Optimal Control Problems ◽  
Control Problems ◽  
Delayed Arguments

scholarly journals Noether’s theorems for the relative motion systems on time scales

2018 ◽  
Vol 3 (2) ◽  
pp. 513-526
Author(s):  
Sheng-nan Gong ◽  
Jing-li Fu
Keyword(s):  
Time Scales ◽  
Relative Motion ◽  
Conserved Quantities ◽  
Noether Symmetries ◽  
Hamilton’S Principle ◽  
Lagrange Equations ◽  
Hamilton's Principle ◽  
Generalized Coordinates ◽  
Delta Derivatives ◽  
Infinitesimal Transformations

AbstractThis paper propose Noether symmetries and the conserved quantities of the relative motion systems on time scales. The Lagrange equations with delta derivatives on time scales are presented for the system. Based upon the invariance of Hamilton action on time scales, under the infinitesimal transformations with respect to the time and generalized coordinates, the Hamilton’s principle, the Noether theorems and conservation quantities are given for the systems on time scales. Lastly, an example is given to show the application the conclusion.

scholarly journals Symmetries for Nonconservative Field Theories on Time Scale

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 552
Author(s):  
Octavian Postavaru ◽  
Antonela Toma
Keyword(s):  
Time Scales ◽  
Dynamic Systems ◽  
Time Scale ◽  
Selection Criteria ◽  
Noether Symmetry ◽  
Field Theories ◽  
Conserved Quantities ◽  
Hamilton’S Principle ◽  
Lagrange Equations ◽  
Infinitesimal Transformations

Symmetries and their associated conserved quantities are of great importance in the study of dynamic systems. In this paper, we describe nonconservative field theories on time scales—a model that brings together, in a single theory, discrete and continuous cases. After defining Hamilton’s principle for nonconservative field theories on time scales, we obtain the associated Lagrange equations. Next, based on the Hamilton’s action invariance for nonconservative field theories on time scales under the action of some infinitesimal transformations, we establish symmetric and quasi-symmetric Noether transformations, as well as generalized quasi-symmetric Noether transformations. Once the Noether symmetry selection criteria are defined, the conserved quantities for the nonconservative field theories on time scales are identified. We conclude with two examples to illustrate the applicability of the theory.

scholarly journals Mei Symmetry and New Conserved Quantities of Time-Scale Birkhoff’s Equations

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Xiang-Hua Zhai ◽  
Yi Zhang
Keyword(s):  
Hamiltonian System ◽  
Time Scales ◽  
Time Scale ◽  
Dynamic Equations ◽  
Conserved Quantities ◽  
Dynamical Processes ◽  
Birkhoffian System ◽  
Special Case ◽  
Mei Symmetry

The time-scale dynamic equations play an important role in modeling complex dynamical processes. In this paper, the Mei symmetry and new conserved quantities of time-scale Birkhoff’s equations are studied. The definition and criterion of the Mei symmetry of the Birkhoffian system on time scales are given. The conditions and forms of new conserved quantities which are found from the Mei symmetry of the system are derived. As a special case, the Mei symmetry of time-scale Hamilton canonical equations is discussed and new conserved quantities for the Hamiltonian system on time scales are derived. Two examples are given to illustrate the application of results.

scholarly journals Conservation Laws for a Delayed Hamiltonian System in a Time Scales Version

Symmetry ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 668 ◽  
Author(s):  
Xiang-Hua Zhai ◽  
Yi Zhang
Keyword(s):  
Hamiltonian System ◽  
Conservation Laws ◽  
Time Scales ◽  
Scientific Research ◽  
Noether Theorem ◽  
Continuous Version ◽  
Difference Analysis ◽  
Delayed Arguments ◽  
New Perspective ◽  
Fowler Equation

The theory of time scales which unifies differential and difference analysis provides a new perspective for scientific research. In this paper, we derive the canonical equations of a delayed Hamiltonian system in a time scales version and prove the Noether theorem by using the method of reparameterization with time. The results extend not only the continuous version of the Noether theorem with delayed arguments but also the discrete one. As an application of the results, we find a Noether-type conserved quantity of a delayed Emden-Fowler equation on time scales.

Time-Scale Version of Generalized Birkhoffian Mechanics and Its Symmetries and Conserved Quantities of Noether Type

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Jin-Yue Chen ◽  
Yi Zhang
Keyword(s):  
Conservation Laws ◽  
Time Scales ◽  
Time Scale ◽  
Symmetry And Conservation Laws ◽  
Conserved Quantity ◽  
Noether Symmetry ◽  
Conserved Quantities ◽  
Birkhoffian System

The time-scale version of Noether symmetry and conservation laws for three Birkhoffian mechanics, namely, nonshifted Birkhoffian systems, nonshifted generalized Birkhoffian systems, and nonshitfed constrained Birkhoffian systems, are studied. Firstly, on the basis of the nonshifted Pfaff-Birkhoff principle on time scales, Birkhoff’s equations for nonshifted variables are deduced; then, Noether’s quasi-symmetry for the nonshifted Birkhoffian system is proved and time-scale conserved quantity is presented. Secondly, the nonshifted generalized Pfaff-Birkhoff principle on time scales is proposed, the generalized Birkhoff’s equations for nonshifted variables are derived, and Noether’s symmetry for the nonshifted generalized Birkhoffian system is established. Finally, for the nonshifted constrained Birkhoffian system, Noether’s symmetry and time-scale conserved quantity are proposed and proved. The validity of the result is proved by examples.

Lie symmetry analysis on time scales and its application on mechanical systems

2018 ◽  
Vol 25 (3) ◽  
pp. 581-592 ◽  
Author(s):  
Xiang-Hua Zhai ◽  
Yi Zhang
Keyword(s):  
Time Scales ◽  
Mechanical Systems ◽  
Lie Symmetry ◽  
Lie Symmetries ◽  
Conserved Quantities ◽  
Lie Symmetry Analysis ◽  
Dynamical Equations ◽  
Symmetry Approach ◽  
Lie Symmetry Approach ◽  
Infinitesimal Transformations

The theory of time scales that can unify and extend continuous and discrete analysis has proved to be more accurate in modeling the dynamic process. The Lie symmetry approach, which is an effective way to deal with different kinds of dynamical equations in a variety of areas of applied science, is to be analyzed on time scales. We begin with the Lie group of point infinitesimal transformations on time scales and its corresponding extensions. And the invariance of dynamical equations on time scales under the infinitesimal transformations is discussed. More specifically, the Lie symmetries for dynamical equations of mechanical systems on time scales including Lagrangian systems on time scales, Hamiltonian systems on time scales, and Birkhoffian systems on time scales are investigated as applications. Thus, the corresponding conserved quantities for mechanical systems on time scales are derived by using the Lie symmetries. Examples are given to illustrate the application of the results.

LVSEM: Past Present and Future

1990 ◽  
Vol 48 (1) ◽  
pp. 364-365
Author(s):  
James B. Pawley
Keyword(s):  
Field Emission ◽  
Line Width ◽  
Time Scales ◽  
Silicon Oxide ◽  
Beam Current ◽  
High Brightness ◽  
High Beam ◽  
Fixed Charges ◽  
Beam Voltage ◽  
Deposited Metal

Past: In 1960 Thornley published the first description of SEM studies carried out at low beam voltage (LVSEM, 1-5 kV). The aim was to reduce charging on insulators but increased contrast and difficulties with low beam current and frozen biological specimens were also noted. These disadvantages prevented widespread use of LVSEM except by a few enthusiasts such as Boyde. An exception was its use in connection with studies in which biological specimens were dissected in the SEM as this process destroyed the conducting films and produced charging unless LVSEM was used.In the 1980’s field emission (FE) SEM’s came into more common use. The high brightness and smaller energy spread characteristic of the FE-SEM’s greatly reduced the practical resolution penalty associated with LVSEM and the number of investigators taking advantage of the technique rapidly expanded; led by those studying semiconductors. In semiconductor research, the SEM is used to measure the line-width of the deposited metal conductors and of the features of the photo-resist used to form them. In addition, the SEM is used to measure the surface potentials of operating circuits with sub-micrometer resolution and on pico-second time scales. Because high beam voltages destroy semiconductors by injecting fixed charges into silicon oxide insulators, these studies must be performed using LVSEM where the beam does not penetrate so far.

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