Weak signal detection is very important in the downhole acoustic telemetry system. This paper introduces the Duffing oscillator weak signal detection method for the downhole acoustic telemetry systems. First, by solving the Duffing equation, analyzed the dynamics characteristic of Duffing oscillator and weak signal detection principle; and then on this basis, built Duffing oscillator circuit ba...

Cogswell, J. J. (1973). Archives of Disease in Childhood, 48, 259. Forced oscillation technique for determination of resistance to breathing in children. A method for measuring total respiratory resistance (RT) using a forced oscillation technique was applied to children between 3 and 12 years of age. RT at midinspiration was higher than airway resistance (Raw) measured on the same children by ...

In this paper, by constructing a class of Philos type functions on time scales, we investigate the oscillation of the following second-order forced nonlinear dynamic equation x(t)− p(t)|x(q(t))|x(q(t)) = e(t), t ∈ T where T is a time scale, p, e : T → R are right dense continuous functions with p > 0, λ > 1 is a constant, and q(t) = t or q(t) = σ(t). Our results not only unify the oscillation o...

Chaos theory has a manifold variety of applications in science and engineering. There are many systems in nature with several stable states, which are separated by energy barriers. When the system can move along the stable states, its dynamics can become quite complex. A simple mechanical model that depicts some of these complex dynamical features is the famous Duffing double-well oscillator (1...

In the field of resonant NEMS design, it is a common misconception that large-amplitude motion, and thus large signal-to-noise ratio, can only be achieved at the risk of oscillator instability. In the present paper, we show that very simple closed-loop control schemes can be used to achieve stable largeamplitude motion of a resonant structure, even when jump resonance (caused by electrostatic s...