FREQUENCY-DEPENDENT NONLINEAR CURRENT OSCILLATION AND CHAOTIC DYNAMICS IN SEMICONDUCTING CARBON NANOTUBES

2010 ◽  
Vol 24 (18) ◽  
pp. 1943-1950
Author(s):  
C. WANG ◽  
J. C. CAO
Keyword(s):  
Nonlinear Dynamics ◽  
Carbon Nanotubes ◽  
Bifurcation Diagram ◽  
Natural Frequency ◽  
Chaotic Dynamics ◽  
Driving Frequency ◽  
Terahertz Frequency ◽  
Frequency Dependent ◽  
Dc Bias ◽  
Spatio Temporal

We have analyzed the spatio-temporal patterns of current self-oscillation under DC bias and terahertz frequency-dependent nonlinear dynamics in semiconducting single-walled zigzag carbon nanotubes (CNTs). It is found that different transport states, including periodic and chaotic, appear with the influence of an external AC signal. The global transitions between periodic and chaotic states are clearly resolved from Poincaré bifurcation diagram. When the driving frequency is fixed at inverse golden mean ratio times natural frequency, the nonlinear CNT system exhibits a more complex transition behavior than at other driving frequencies.

scholarly journals Complex partial synchronization patterns in networks of delay-coupled neurons

2019 ◽  
Vol 377 (2153) ◽  
pp. 20180128 ◽  
Author(s):  
D. Nikitin ◽  
I. Omelchenko ◽  
A. Zakharova ◽  
M. Avetyan ◽  
A. L. Fradkov ◽  
...  
Keyword(s):  
Nonlinear Dynamics ◽  
Temporal Dynamics ◽  
Delay Systems ◽  
Theme Issue ◽  
Partial Synchronization ◽  
Multiplex Network ◽  
Control Scheme ◽  
Non Local ◽  
Spatio Temporal ◽  
Fast Oscillations

We study the spatio-temporal dynamics of a multiplex network of delay-coupled FitzHugh–Nagumo oscillators with non-local and fractal connectivities. Apart from chimera states, a new regime of coexistence of slow and fast oscillations is found. An analytical explanation for the emergence of such coexisting partial synchronization patterns is given. Furthermore, we propose a control scheme for the number of fast and slow neurons in each layer. This article is part of the theme issue ‘Nonlinear dynamics of delay systems’.

An integrated numerical–experimental study on the optimum utilization of carbon nanotubes in laminated composites

2016 ◽  
Vol 19 (2) ◽  
pp. 231-258 ◽  
Author(s):  
Mahmood Heshmati ◽  
Bandar Astinchap ◽  
Masoud Heshmati ◽  
Mohammad Hosein Yas ◽  
Yasser Amini
Keyword(s):  
Carbon Nanotubes ◽  
Natural Frequency ◽  
Experimental Studies ◽  
Distribution Patterns ◽  
Weight Percent ◽  
Composite Beams ◽  
Linear Distribution ◽  
Fundamental Natural Frequency ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

In this paper, a set of numerical and experimental studies are performed to improve mechanical and vibrational properties of carbon nanotubes-reinforced composites. First, at a design concept level, linear distribution patterns of multi-walled carbon nanotubes through the thickness of a typical beam is adopted to investigate its fundamental natural frequency for a given weight percent of multi-walled carbon nanotubes. Both Timoshenko and Euler-Bernoulli beam theories are used in the derivation of the governing equations. The finite element method is employed to obtain a numerical approximation of the motion equation. Next, based on the introduced distribution patterns, laminated multi-walled carbon nanotubes-reinforced polystyrene-amine composite beams are fabricated. Static and experimental modal tests are performed to measure the effective stiffness and fundamental natural frequencies of the fabricated composite beams. Also, in order to generate realistic model to investigate the material properties of fabricated composite beams, the actual tensile specimens of multi-walled carbon nanotubes/polystyrene-amine composites are successfully fabricated and the tensile behaviors of both pure matrix and composites are investigated. To better interfacial bonding between carbon nanotubes and polymer, a chemical treatment is performed on carbon nanotubes. It is seen that the addition of a few wt. % of multi-walled carbon nanotubes make considerable increase in the Young's modulus and the tensile strength of the composite. It is observed from the free vibration tests that the uniform distribution of multi-walled carbon nanotubes results in an increase of 9.5% in the fundamental natural frequency of the polymer cantilever beam, whereas using the symmetric multi-walled carbon nanotube distribution increased its fundamental natural frequency by 17.32%.

scholarly journals Current conserving theory for frequency dependent noise power under dc bias

2018 ◽  
Vol 20 (1) ◽  
pp. 013036
Author(s):  
Jiangtao Yuan ◽  
Yin Wang ◽  
Jian Wang
Keyword(s):  
Noise Power ◽  
Frequency Dependent ◽  
Dc Bias

scholarly journals Investigation of the Effect of Additive White Noise on the Dynamics of Contact Interaction of the Beam Structure

2019 ◽  
Author(s):  
Ольга Салтыкова ◽  
Olga Saltykova ◽  
Александр Кречин ◽  
Alexander Krechin
Keyword(s):  
Nonlinear Dynamics ◽  
White Noise ◽  
Contact Interaction ◽  
Geometric Nonlinearity ◽  
Chaotic Dynamics ◽  
Kutta Method ◽  
Beam Structure ◽  
Runge Kutta Method ◽  
Additive White Noise ◽  
The Finite Difference Method

The purpose of this work is to study and scientific visualization the effect of additive white noise on the nonlinear dynamics of beam structure contact interaction, where beams obey the kinematic hypotheses of the first and second approximation. When constructing a mathematical model, geometric nonlinearity according to the T. von Karman model and constructive nonlinearity are taken into account. The beam structure is under the influence of an external alternating load, as well as in the field of additive white noise. The chaotic dynamics and synchronization of the contact interaction of two beams is investigated. The resulting system of partial differential equations is reduced to a Cauchy problem by the finite difference method and then solved by the fourth order Runge-Kutta method.

Numerical Modeling of the Eigenmodes and Eigenfrequencies of Carbon Nanotubes under the Influence of Defects

2012 ◽  
Vol 21 ◽  
pp. 159-164 ◽  
Author(s):  
Ali Ghavamian ◽  
Andreas Öchsner
Keyword(s):  
Finite Element Method ◽  
Carbon Nanotubes ◽  
Natural Frequency ◽  
Single Walled Carbon Nanotubes ◽  
Vibrational Properties ◽  
The Finite Element Method ◽  
Single Walled Carbon ◽  
Si Doping ◽  
Walled Carbon Nanotubes ◽  
Mathematical Relations

Two configurations of perfect single walled carbon nanotubes (armchair and zigzag) were simulated based on the finite element method. Then, three most likely defects (Si-doping, carbon vacancy and perturbation) were introduced to the models to represent defective forms of single walled carbon nanotubes (SWCNTs). Finally, the vibrational properties of perfect and defective carbon nanotubes were evaluated and compared. The results showed that SWCNTs have a natural frequency with a rather high value between 18.69 and 24.01 GHz. In the consideration of the natural frequency of the defective SWCNTs, it was also observed that the existence of any type of defects or irregularities leads to a lower value of natural frequency and vibrational stability. Simple mathematical relations which express the change in natural frequency versus the percentage of the defect were also presented. This can be very useful to realistically estimate the influence of defects of different amounts on the vibrational behavior of carbon nanotubes.

Nonlinear Dynamics of a Taut String with Material Nonlinearities

2000 ◽  
Vol 123 (1) ◽  
pp. 53-60 ◽  
Author(s):  
M. J. Leamy ◽  
O. Gottlieb
Keyword(s):  
Nonlinear Dynamics ◽  
Dynamic Response ◽  
Natural Frequency ◽  
Continuum Mechanics ◽  
Finite Deformation ◽  
Multiple Scales ◽  
String Model ◽  
Taut String ◽  
Linear Material ◽  
Nonlinear String

A spatial string model incorporating a nonlinear (and nonconservative) material law is proposed using finite deformation continuum mechanics. The resulting model is shown to reduce to the classical nonlinear string when a linear material law is used. The influence of material nonlinearities on the string’s dynamic response to excitation near a transverse natural frequency is shown to be small due to their appearance at high orders only. Material nonlinearities appear at low order in the equations for excitation near a longitudinal natural frequency, and a solution for this case is developed by applying a second order multiple scales method directly to the partial differential equations. The material nonlinearities are found to influence both the degree of nonlinearity in the response and its softening or hardening nature.

Sign in / Sign up

Export Citation Format

Share Document