Results 11 to 20 of about 2,719 (189)
A survey on algebraic and explicit non-algebraic limit cycles in planar differential systems
Expositiones Mathematicae, 2021 In the qualitative theory of differential equations in the plane one of the most difficult objects to study is the existence of limit cycles. There are many papers dedicated to this subject. Here we will present a survey mainly dedicated to the algebraic and explicit non-algebraic limit cycles of the polynomial differential systems in R and of the ...
Llibre, Jaume, Zhang, Xiang
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A Class of Quintic Kolmogorov Systems with Explicit Non-algebraic Limit Cycle [PDF]
Journal of Siberian Federal University. Mathematics & Physics, 2019 Various physical, ecological, economic, etc phenomena are governed by planar differential systems. Sub- sequently, several research studies are interested in the study of limit cycles because of their interest in the understanding of these systems. The aim of this paper is to investigate a class of quintic Kolmogorov systems, namely systems of the form
Bendjeddou, Ahmed, Grazem, Mohamed
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A class of differential systems of even degree with exact non-algebraic limit cycles [PDF]
Studia Universitatis Babes-Bolyai Matematica, 2020 Up until now all the polynomial differential systems for which non-algebraic limit cycles are known explicitly have degree odd. Here we show that already that there are polynomial systems of degree even has an explicit limit cycle which is not algebraic. To our knowledge, there are no such type of examples in the literature.
Abdelkrim Kina +2 more
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Explicit Non Algebraic Limit Cycle for a Discontinuous Piecewise Differential Systems Separated by One Straight Line and Formed by Linear Center and Linear System Without Equilibria [PDF]
Tatra Mountains Mathematical Publications, 2021 Abstract In this paper, we deal with the discontinuous piecewise differential linear systems formed by two differential systems separated by a straight line when one of these two differential systems is a linear without equilibria and the other is a linear center.
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Organic Materials of Tomorrow: Horizons of Artificial Intelligence
Advanced Materials, EarlyView.This review examines machine learning techniques accelerating the discovery of organic semiconductors by linking molecular structure to properties. Key methods include graph neural networks, generative models, and active learning. Applications to organic photovoltaics demonstrate practical impact.
Harold Mena +3 more
wiley +1 more source
Continuum Mechanics Modeling of Flexible Spring Joints in Surgical Robots
Advanced Robotics Research, EarlyView.A new mechanical model of a tendon‐actuated helical extension spring joint in surgical robots is built using Cosserat rod theory. The model can implicitly handle the unknown contacts between adjacent coils and numerically predict spring shapes from straight to significantly bent under actuation forces.
Botian Sun +3 more
wiley +1 more source
Advanced Robotics Research, EarlyView.This work presents a state‐adaptive Koopman linear quadratic regulator framework for real‐time manipulation of a deformable swab tool in robotic environmental sampling. By combining Koopman linearization, tactile sensing, and centroid‐based force regulation, the system maintains stable contact forces and high coverage across flat and inclined surfaces.
Siavash Mahmoudi +2 more
wiley +1 more source
Physical Origin of Temperature Induced Activation Energy Switching in Electrically Conductive Cement
Advanced Science, EarlyView.The temperature‐induced Arrhenius activation energy switching phenomenon of electrical conduction in electrically conductive cement originates from structural degradation within the biphasic ionic‐electronic conduction architecture and shows percolation‐governed characteristics: pore network opening dominates the low‐percolation regime with downward ...
Jiacheng Zhang +7 more
wiley +1 more source
Advanced Science, EarlyView.A conversion‐resolved constitutive framework is developed for the hydrogen‐based direct reduction of iron oxide pellets. Effective reaction and transport timescales are inferred directly from measured trajectories and mapped against operating conditions, pellet architecture, and composition. The analysis reveals how late‐stage transport control emerges
Anurag Bajpai +3 more
wiley +1 more source
Explicit limit cycles of a family of polynomial differential systems
Electronic Journal of Differential Equations, 2017 We consider the family of polynomial differential systems $$\displaylines{ x' = x+( \alpha y-\beta x) (ax^2-bxy+ay^2) ^{n}, \cr y' = y-( \beta y+\alpha x) (ax^2-bxy+ay^2) ^{n}, }$$ where a, b, $\alpha $, $\beta $ are real constants and n is ...
Rachid Boukoucha
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