The use of optical micro-ring resonators as a platform for quantitative and qualitative biosensing applications was explored. Vertically coupled, high refractive index micro-ring resonators, used as sensing elements, were fabricated on silicon chips by photolithographic techniques. An optical reader system consisting of a near-infrared broad band light source and an optical spectrum analyzer were employed for data acquisition. Micro-ring resonator surfaces were modified with specific target receptors, including antibodies and single-stranded DNA oligonucleotides. The system was successfully used for label-free, specific, and rapid detection of whole bacterial cells, proteins and nucleic acids.

The potentiostatic method for determining the steady‐state parameters for anodic oxidation of the valve metals is examined in relation to present models for the conduction properties of the oxides. It is shown that despite the fact that potentiostatic conditions correspond to nonsteady‐state conditions, the steady‐state field coefficient (reciprocal Tafel slope) may be determined accurately, and relatively easily, from such measurements. Data for aluminum are presented in illustration and found to be in accord with an equation of the form , where is the current density, the field strength, and α, γ, and δ positive constants for isothermal conditions. The values of γ and δ obtained are in good agreement with values obtained previously using a method in which steady‐state conditions were maintained during measurement. The agreement lends further support for the inclusion of the term in in the conduction equation.

A novel and sensitive experimental technique has been developed and employed to measure the field variation of the Tafel slope at 25 °C for the steady-state anodic oxidation of aluminium. The data have been fitted to an equation of the form I = α exp [γE − δE2] where I and E are the current density and field strength in the anodic film and α, γ, and δ are positive constants for isothermal conditions. Some information concerning the field variation of the interfacial potentials has also been obtained.