No abstract

A method of sterilizing intermittent positive pressure ventilators is described, using 10 per cent ethylene oxide in 90 per cent carbon dioxide. This method can be used for any type of machine available, and several different methods are described to suit the variety of ventilators. Essentially, ethylene oxide is introduced into a large bag enclosing the ventilator, which is allowed to cycle for up to 24 hours. The bag is made of Terykne, proofed with Neoprene to prevent diffusion and dilution of the gas. A simple chemical method of monitoring the process is also described.

No abstract

Sub-wavelength grating, surface enhanced Raman, dispersion relation We fabricated and measured the far-field optical properties of a sub-wavelength Si3N4 (silicon nitride) two dimensional grating. Frequency-dependent transmission measurements from a white-light source revealed that both transverse magnetic (TM) and transverse electric (TE) modes were excited on the grating. We determined the dispersion relations of the modes by tilting the sample with respect to the incoming light beam and measuring the frequency shift of the absorption features. By comparing to a simple model, we determined the effective refractive index for the TM and TE modes and the geometrical constants for the grating. This information enables gratings with desired optical properties to be designed and fabricated. The application of the sub-wavelength grating for surface enhanced Raman scattering (SERS) is demonstrated.