Results 21 to 30 of about 1,422 (148)

Uniform isochronous cubic and quartic centers: Revisited

Journal of Computational and Applied Mathematics, 2017
In this paper we completed the classification of the phase portraits in the Poincaré disc of uniform isochronous cubic and quartic centers previously studied by several authors. There are three and fourteen different topological phase portraits for the uniform isochronous cubic and quartic centers respectively.
Joan C. Artés, Jackson Itikawa, Jaume Llibre   +2 more
openaire   +4 more sources

The Problem of Bicenter and Isochronicity for a Class of Quasi Symmetric Planar Systems

Abstract and Applied Analysis, 2014
We study a class of quasi symmetric seventh degree systems and obtain the conditions that its two singular points can be two centers at the same step by careful computing and strict proof. In addition, the condition of an isochronous center is also given.
Du Chaoxiong
doaj   +1 more source

Phase portraits of uniform isochronous quartic centers

Journal of Computational and Applied Mathematics, 2015
In this paper we classify the global phase portraits in the Poincaré disc of all quartic polynomial differential systems with a uniform isochronous center at the origin such that their nonlinear part is not homogeneous.
Jackson Itikawa, Jaume Llibre
openaire   +3 more sources

Frontier Research on Isochronous Accelerator and Its Applications at China Institute of Atomic Energy Since the 21st Century

Yuanzineng kexue jishu
Isochronous cyclotrons hold an indispensable position in national security and the science and technology innovation system. In the new era, there is an urgent demand for breakthroughs in compact structure, high energy, and high beam intensity of ...
ZHANG Tianjue, FU Wei, WANG Chuan, YIN Zhiguo, JIA Xianlu, AN Shizhong, LI Pengzhan, ZHOU Hongji, SONG Guofang, CHEN Xinyu
doaj   +1 more source

Integrability and Pseudo-Linearizable Conditions in a Quasi-Analytic System

Abstract and Applied Analysis, 2012
This paper deals with the problems of integrability and linearizable conditions at degenerate singular point in a class of quasianalytic septic polynomial differential system.
Feng Li, Yusen Wu
doaj   +1 more source

A global isochronous center is linear

, 2021
Let $X$ be a polynomial vector field in $\mathbb{R}^2$ which, after one-point compactification of the plane, has a punctured neighbourhood $\dot U$ of the point at infinity which is foliated by closed orbits of $X$. If the period function of $X$ in $\dot U$ is bounded from below by a positive constant, $X$ is necessarily linear, hence conjugated, up to
openaire   +2 more sources

Center-focus and isochronous center problems for discontinuous differential equations

Discrete and Continuous Dynamical Systems, 2000
The authors study planar systems with a line of discontinuities. They use a geometrical proof to show a relation between the order of degeneracy of the critical point (\((m,k)\)-monodromic point) of the discontinuous differential equations and the degeneracy of the associated two smooth component differential equations.
Coll, B., Gasull, A., Prohens, R.
openaire   +2 more sources

Microstructural Evolution and Vacancy Defect Formation in Mn–Mo–Ni RPV Steel Under Low Cycle Fatigue: Insights From EBSD and PALS

Advanced Engineering Materials, EarlyView.
Low‐cycle fatigue damage in Mn–Mo–Ni reactor pressure vessel steel is examined using a combined electron backscatter diffraction and positron annihilation lifetime spectroscopy approach. The study correlates texture evolution, dislocation substructure development, and vacancy‐type defect formation across uniform, necked, and fracture regions, providing
Apu Sarkar, Dhanadeep Dutta, G. Bharat Reddy   +2 more
wiley   +1 more source

Periodic oscillators, isochronous centers and resonance [PDF]

Nonlinearity, 2019
Abstract An oscillator is called isochronous if all motions have a common period. When the system is forced by a time-dependent perturbation with the same period the dynamics may change and the phenomenon of resonance can appear. In this context, resonance means that all solutions are unbounded.
Rafael Ortega, David Rojas
openaire   +5 more sources

A Geometric Characterization of Steady Laminar Flow

Communications on Pure and Applied Mathematics, EarlyView.
ABSTRACT We study the steady states of the Euler equations on the periodic channel or annulus. We show that if these flows are laminar (layered by closed non‐contractible streamlines which foliate the domain), then they must be either parallel or circular flows.
Theodore D. Drivas, Marc Nualart
wiley   +1 more source