Electrochemical impedance has been used to study the adsorption at glassy carbon electrodes of guanine, its corresponding nucleoside, guanosine, and adenine. Impedance studies at different concentrations and applied potentials show clearly that all three bases are adsorbed on the electrode, blocking the surface. Irradiating the electrode with low-frequency (20 kHz) ultrasound whilst recording t...

During this program we have had several major accomplishments. These include finalizing our prior work on simple anisotropic surfaces consisting of discrete regions of homogeneous impedance values, and demonstrating them in the form of several useful structures. Examples include beam shifting structures, and scattering control surfaces. We have also developed a new method for patterning anisotr...

In this paper, a problem on Rayleigh surface wave in an isotropic micropolar elastic solid half-space with impedance boundary conditions is investigated. It is assumed that the normal force traction, shear force traction and shear couple traction vary linearly with the normal displacement component, tangential displacement component and microrotation component multiplied by the frequency, where...

Apparatus has been designed and constructed for the measurement of the electric impedance of suspensions of Arbacia eggs in sea water to alternating currents of frequencies from one thousand to fifteen million cycles per second. This apparatus is simple, rugged, compact, accurate, and rapid. The data lead to the conclusions that the specific resistance of the interior of the egg is about 90 ohm...

As an alternative to chromate conversion coatings, rare-earth coatings especially cerium, because of the low toxicity, have attracted considerable attention. Using dip immersion method, cerium-based conversion coating was deposited on aluminum 2024. Corrosion resistance was studied in 3.5 wt.% NaCl solution using potentiodynamic polarization, electrochemical impedance spectroscopy, and surface ...

We unveil the connection between the acoustic impedance along a flat surface and the reflected acoustic wavefront, in order to empower a wide wariety of novel applications in acoustic community. Our designed flat surface can generate double reflections: the ordinary reflection and the extraordinary one whose wavefront is manipulated by the proposed impedance-governed generalized Snell's law of ...

In this study, the effect of molybdate on the electrochemical behavior and semi-conductive properties of duplex stainless steel 2205 passive film at NaCl solutions was investigated. Cyclic potentiodynamic polarization, impedance spectroscopy, mott-schottky plots and scanning electron microscopy (SEM) were used to study the passive behavior. Polarization curves showed that the corrosion current ...

The use of acoustics to determine the pore properties of soils, such as porosity, permeability, and tortuosity, is well established. A theoretical surface impedance and complex bulk wavenumber was developed by K. Attenborough for porous media that incorporated the soil pore properties as parameters [J. Acoust. Soc. Am. 73, 785-799 (1983)]. Acoustic level difference measurements were used as a n...

The beam impedance of monopole modes in a pipe with periodic, smooth and shallow corrugation has been calculated. The approach uses an orthogonal TM field expansion with Bessel functions and an impedance boundary condition, which takes into account resistive wall effects. The approach is valid for corrugations with period lengths larger, smaller and of the same order as the free space wavelengt...

An equivalent circuit model for predicting the frequency response of a square ring slot frequency selective surface (SRS-FSS) for normal incidence is described. The proposed FSS consists of an array of square patches centered within a wire grid. The presented circuit model is formed by the impedance of the wire grid that is parallel with the impedance of the patch array, also the mutual couplin...