An acoustic based, laser induced breakdown method for determining the sizes and concentrations of nanoparticles.

An acoustic, laser induced breakdown (LIBD) method has been developed for determining the sizes and concentrations of nano-sized colloids. The size distributions from a mixture of aquatic nanoparticles are determined by measuring amplitudes of plasma shockwave that are fitted to multi-curve Gaussian distributions displayed in separate peaks with positions corresponding to particle sizes and areas being proportional to concentrations.

Kinetic analysis of supported Ni-catalyzed CO2/CH4 reactions using photoacoustic spectroscopy.

CO2 photoacoustic spectroscopy was employed to analyze kinetically the CO2/CH4 reaction catalyzed by 14 wt% Ni/Al2O3 and 14 wt% Ni/TiO2. The catalytic reaction was carried out in the temperature range of 673-923 K at various partial pressures of CO2 and CH4 (40 Torr total pressure) in a closed-circulating reactor system. The CO2 photoacoustic signal, measured by using a differential photoacoustic cell, was recorded as a function of reaction time.

Detection method for ionic species based on the electroacoustic effect.

The development and application of a new ion detection method based on the electroacoustic (EA) effect is described. An EA signal, produced by applying a pulsed-type electric field to an electrolyte solution in an electroacoustic cell, is dependent on the electrical and thermal properties of the electrolyte and can be detected by using a conventional gas microphone system. The EA signals, generated in this fashion, are proportional to the square of the amplitude of the pulsed-type electric field and show an inverse dependence on the modulated frequency, as found in other acoustic detection systems.