Nanometer sized cavities arranged as a subwavelength metallic grating can provide omni-directional and complete absorption of light. We present an explanation of this extraordinary phenomenon as a collective resonant response of a system based on a surface impedance model. This model gives a straightforward way to design systems for optimum light trapping performance and as well gives fundament...

In a previous paper, we proposed the impedance perception technique, by which the stiffness matrix that constrains the motion-force relation of the robot’s end-effector is estimated on-line, and the uncertainties of the estimates are evaluated. Based on this technique, this paper proposes a method of extracting information on local properties of a cylindrical curved surface, including normal di...

In recent years, impedance measurement method by piezoelectric (PZT) wafer activesensor (PWAS) has been widely adopted for non-destructive evaluation (NDE). In this method, theelectrical impedance of a bonded PWAS is used to detect a structural defect. The electro-mechanicalcoupling of PZT materials constructs the original principle of this method. Accordingly, the electricalimpedance of PWAS c...

An accurate and practical surface impedance boundary condition in the time domain has been developed for application to broadband-frequency simulation in aeroacoustic problems. To show the capability of this method, two kinds of numerical simulations are performed and compared with the analytical/experimental results: one is acoustic wave reflection by a monopole source over an impedance surfac...

A variational method is given for determining the essential supremum of the surface impedance of a partially coated perfect conductor from a knowledge of the far field pattern of the time-harmonic electric field at fixed frequency. It is assumed that the shape of the scatterer has been determined (e.g., by solving the far field equation and using the linear sampling method). Numerical examples ...

The conducting polymer polypyrrole (PPy) was electrochemically grown on hydrogel scaffolds deposited on the surface of microfabricated neural prosthetic devices. It is shown that the pyrrole monomer can be grown vertically through the hydrogel layer up to the surface without affecting the adjacent sites on the probes. The electrochemical properties of the conducting polymer-modified hydrogels w...

We present details of an experimental method to measure the field modulated surface resistance (dR,/dH) of superconducting films accurately, which enables both field and temperature sweep experiments and is particularly useful for low-field or near T, measurements. The complex surface impedance Z,(H,T) =R,(H,T) + iX,(H, T) can also be simultaneously measured. This technique utilizes specially b...

The normal sound absorption coefficients of two different test objects in an impedance tube are measured with two different methods: The standing wave ratio method (ISO 10534-1:1996) and the transfer function method (ISO 10534-2:1998). From the latter is the specific acoustic impedance ratio calculated. The test objects are two cellular plastics: AC 30 S and FIRE 30 VF (both are 30 mm thick), t...

When the end-effector of a robot is slid on a flat surface, the stiffness matrix obtained by linear fitting of position and force contains information not only on the stiffness coefficient and on the normal direction, but also on the friction coefficient. This paper proposes a new method for extracting information on those properties from the stiffness matrix provided by the impedance perceptio...

The effect of flow over an acoustic liner is generally described by the Myers impedance condition. The use of this impedance condition in time-domain numerical simulations has been plagued by stability issues, and various ad hoc techniques based on artificial damping or filtering have been used to stabilise the solution. The theoretical issue leading to the ill-posedness of this impedance condi...