Conjugated polyelectrolyte (CPE) interfacial layers present a powerful way to boost the I-V characteristics of organic photovoltaics. Nevertheless, clear guidelines with respect to the structure of high-performance interlayers are still lacking. In this work, impedance spectroscopy is applied to probe the dielectric permittivity of a series of polythiophene-based CPEs. The presence of ionic pen...

We describe the design of a dry electrode sensor for biopotential measurement applications (ENOBIO) designed to eliminate the noise and inconvenience associated to the use of electrolytic gel. ENOBIO uses nanotechnology to remove gel-related noise, as well as maintaining a good contact impedance to minimise interference noise. The contact surface of the electrode will be covered with an array/f...

Light propagation in a random system of isotropic magnetodielectric layers is studied numerically and analytically. It is shown that if the values of permittivity and permeability are randomly distributed, whereas the characteristic impedance does not change throughout the system, the Lyapunov exponent (the inverse localization length) grows with the angle of incidence and does not depend on th...

Brookhaven National Laboratory was requested to conduct a literature survey for the best available cement to use in the proposed casing patch as part of the Geothermal Drilling Organization (GDO) project on remediation of deformed casings. A total of 50 wells has been identified with deformed production casing in Unocal’s portion of The Geysers geothermal field. Reduced internal diameter and ca...

Acoustic bottom-interacting measurements from the Shallow Water '06 experiment experiment (frequency range 1-20 kHz) are presented. These are co-located with coring and stratigraphic studies showing a thin (approximately 20 cm) higher sound speed layer overlaying a thicker (approximately 20 m) lower sound speed layer ending at a high-impedance reflector (R reflector). Reflections from the R ref...

A novel method for calculation of PEM fuel cell cathode impedance from charge and mass conservation equations is developed. The catalyst layer separated into N sub–layers. Assuming that the steady–state variables along sub–layer are constant, linearized Fourier–transformed problem overpotential oxygen concentration perturbations solved analytically on a single sub–layer. solution leads to recur...

This short note describes some simple acoustical wave experiments that explain the physics of reflection and transmission coefficient formulae for normal incidence P-waves. The experiments help us to understand the mathematical expressions for the reflection and transmission coefficients for displacement and pressure that are frequently used in seismology. Figure 1. The figure shows a boundary ...

In this paper, a signal processing method is proposed to estimate the low and high-frequency impedances of power systems using several short-term low power signal injections for a frequency range of 0-150 kHz. This frequency range is very important, and thusso it is considered in the analysis of power quality issues of smart grids. The impedance estimation is used in many power system applicati...

We consider a Fabry-Perot resonance a transmission band edge resonance in periodic layered structures involving birefringent layers. In a previous publication Phys. Rev. E 72, 036619 2005 we have shown that the presence of birefringent layers with misaligned in-plane anisotropy can dramatically enhance the performance of the photonic-crystal resonator. It allows us to reduce its size by an orde...

Approximate expressions are given for the characteristic impedance and propagation wavenumber for linear acoustic transmission through a gas enclosed in a rigid cylindrical duct. These expressions are most complicated in the transition zone where the thermoviscous boundary layers are on the order of the tube radius. The approximations are accurate to within 1% for all frequencies and tube diame...