scholarly journals Work done by a periodical external force on an overdamped harmonic oscillator with frequency fluctuation and energetic stochastic resonance

2013 ◽  
Vol 62 (19) ◽  
pp. 190502
Author(s):  
Zhang Liang-Ying ◽  
Cao Li ◽  
Wu Da-Jin
Keyword(s):  
Harmonic Oscillator ◽  
Stochastic Resonance ◽  
External Force ◽  
Frequency Fluctuation ◽  
Work Done

Stochastic resonance of a damped oscillator with frequency fluctuation driven by a periodic external force

2012 ◽  
Vol 21 (12) ◽  
pp. 120502 ◽  
Author(s):  
Ling-Ying Zhang ◽  
Guo-Xiang Jin ◽  
Li Cao ◽  
Zhi-Yun Wang
Keyword(s):  
Stochastic Resonance ◽  
External Force ◽  
Frequency Fluctuation ◽  
Damped Oscillator

scholarly journals Crystallization of Polymers under the Influence of an External Force Field

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2078
Author(s):  
Rajdeep Singh Payal ◽  
Jens-Uwe Sommer
Keyword(s):  
External Force ◽  
Melting Behavior ◽  
Mechanical Work ◽  
Stem Length ◽  
Heat Of Fusion ◽  
Strong Increase ◽  
Lamellar Thickness ◽  
Equilibrium System ◽  
External Force Field ◽  
Work Done

We simulated the crystallization and melting behavior of entangled polymer melts using molecular dynamics where each chain is subject to a force dipole acting on its ends. This mimics the deformation of chains in a flow field but represents a well-defined equilibrium system in the melt state. Under weak extension within the linear response of the chains, the mechanical work done on the system is about two orders of magnitude smaller as compared with the heat of fusion. As a consequence, thermodynamic and simple arguments following the secondary nucleation model predict only small changes of the crystalline phase. By contrast, an increase of the stem length up to a factor of two is observed in our simulations. On the other hand, the lamellar thickening induced by the external force is proportional to the increase of the entanglement length in the melt prior to crystallization as measured by the primitive path method. While the mechanical work done on the system is only a small perturbation for thermodynamics of polymer crystallization, the change of the primitive path is large. This suggests that a strong increase in the lamellar thickness induced, by external deformation, a topological rather than a thermodynamic origin.

Entropic stochastic resonance without external force in oscillatory confined space

2015 ◽  
Vol 142 (19) ◽  
pp. 194109 ◽  
Author(s):  
Huai Ding ◽  
Huijun Jiang ◽  
Zhonghuai Hou
Keyword(s):  
Stochastic Resonance ◽  
External Force ◽  
Confined Space

Comment on: Quantum theory of a non-Hermitian time-dependent forced harmonic oscillator having 𝒫𝒯 symmetry

2020 ◽  
Vol 35 (01) ◽  
pp. 2075001
Author(s):  
Naima Mana ◽  
Mustapha Maamache
Keyword(s):  
Quantum Theory ◽  
Harmonic Oscillator ◽  
External Force ◽  
Time Dependent ◽  
Normalization Condition ◽  
Complex Time ◽  
Linear Invariant ◽  
Novel Concept

Pedrosa et al.1 have recently used a [Formula: see text] symmetric linear invariant to study a unidimensional time-dependent [Formula: see text] symmetric harmonic oscillator with a complex time-dependent [Formula: see text] symmetric external force. We show in this comment that the normalization condition of the eigenfunctions of the invariant is not verified as claimed in Ref. 1. In order to obtain the normalization condition, we introduce a novel concept of the pseudoparity-time (pseudo-[Formula: see text]) symmetry.

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