This study is concerned with a new adaptive impedance control strategy to compensate for unknown time-varying environment stiffness and position. The uncertainties are expressed by Function Approximation Technique (FAT), which allows the update laws to be derived easily using Lyapunov stability theory. Computer simulation results are presented to validate the effectiveness of the proposed strat...

This paper reports the initial results of a test series to evaluate a method for determining the normal incidence impedance of a locally reacting acoustically absorbing liner, located on the lower wall of a duct in a grazing incidence, multi-modal, nonprogressive acoustic wave environment without ow. This initial evaluation is accomplished by testing the methods' ability to converge to the know...

Passive and active (voltage- and time-dependent) membrane properties of trigeminal root ganglion neurons of decerebrate guinea pigs have been determined using frequency-domain analyses of small-amplitude perturbations of membrane voltage. The complex impedance functions of trigeminal ganglion neurons were computed from the ratios of the fast Fourier transforms of the intracellularly recorded vo...

OBJECTIVE Mitral regurgitation (MR) is generally characterised as exhibiting a 'low impedance leak into the left atrium'. This notion is widely accepted without measured impedance data. The aim of this study was to define the impedance to retrograde and forward blood flow and to examine hydraulic (pressure-volume) and mechanical (stress-shortening) function in chronic severe MR. METHODS A mat...

Impedance spectra of the hydrogen evolution reaction, HER, at low cathodic overpotentials were analyzed on the basis of the theoretical admittance/frequency function, initially derived for the Volmer-Heyrovsky-Tafel reaction mechanism involving the hydrogen insertion (absorption + diffusion) step. General principles of the impedance spectroscopy for HER are discussed using schematically constru...

Background: Pulsed amperometric detection is a relatively new method for detection of ions and especially nonelectrolytes such as carbohydrates in aqueous solutions. Pulsed amperometric detection relies on a redox reaction while electrochemical impedance simply measures the real and capacitive resistant of the solution. There is a correlation between the real impedance of a solution and the ion...

We deal with the acoustic inverse scattering problem for detecting an obstacle with mixed boundary conditions from the far field map. We show how the geometric properties and the material parameter distributed on the surface are involved in the obstacle reconstruction numerically. The main advance of this research on our recently work (SIAM J. Applied Math, 67(4), 2007) is the higher-order asym...

This study quantifies the dynamic attachment and spreading of porcine pulmonary artery endothelial cells (PPAECs) on optically thin, indium tin oxide (ITO) biosensors using simultaneous differential interference contrast microscopy (DICM) and electrical microimpedance spectroscopy. A lock-in amplifier circuit monitored the impedance of PPAECs cultivated on the transparent ITO bioelectrodes as a...

In a simply connected planar domain D a pair of Cauchy data of a harmonic function u is given on an accessible part of the boundary curve, and on the nonaccessible part u is supposed to satisfy a homogeneous impedance boundary condition. We consider the inverse problems to recover the non-accessible part of the boundary or the impedance function. Our approach extends the method proposed by Kres...

at the highest signal levels, the masking function for the off-frequency condition seems to become more linear. while some basilar membrane data show more linear growth at high levels, others do not. aim of the present study is to assess function of masking at high levels regarding its clinical appearance. in this experiment we evaluated the hearing thresholds of three different signals (wide-b...