Real-time coloured visualization of phase flows by the schlieren method

A coloured real-time visualizer of optical inhomogeneities comprising a bichromatic schlieren system, video camera and colour monitor has been developed. The schlieren system represents a function Foucault-Hilbert transformation provided with an amplitude spatial frequency filter, or a quadrant Foucault knife edge. Two colour-coded complementary Toepler-grams are obtained in the exit plane of this schlieren system. Their summed image is then recorded by the video camera and displayed on the screen of the colour monitor. The schlieren photograph of internal gravity waves, generated by the cylindrical body motion in the reservoir filled with the stratified liquid, is presented.     

Magnetic nanoparticles for high-sensitivity detection on nucleic acids via superconducting-quantum-interference-device-based immunomagnetic reduction assay

In this work, we investigate the feasibility of detecting quantitatively DNA molecules utilizing the technology named after the immunomagnetic reduction (IMR) assay. Magnetic nanoparticles dispersed in a phosphate buffer saline solution were bio-functionalized with probing single-strand DNA. A superconducting quantum interference device (SQUID) ac magnetosusceptometer was employed to detect IMR signals related to the concentration of the target DNA. The results reveal that use of IMR assay had merits such as a high convenience level, e.g. wash-free processes and high sensitivity, down to pM, for DNA detection.     

The application of an electro-optical frequency modulator with a rotating electric field in optical Doppler velocimeters

The possibility of using an electro-optical frequency modulator with a rotating electric field (MREF) in LDV is discussed. Prototype systems measuring one component of the velocity vector are described. Photographs of the experimental signals obtained are given.     

A laser Doppler velocimeter which measures the three components of velocity

A device for simultaneously measuring the three orthogonal components of a velocity vector is described. The system uses a laser beam passing twice through the region of flow under investigation. This allows one to determine the third component using only forward scattering. Vector diagrams which explain the mode of operation and experimental signals are given.     

The application of an optical Doppler frequency discriminator in a laser velocimeter

A laser velocimeter is described which uses an optical Doppler frequency discriminator in the form of a spherical mirror confocal Fabry-Perot interferometer (SFPI). The SFPI pass band is made to coincide with the laser frequency using a system of external control. Experimental results are given.     

Analysis of optical compensating schemes of laser Doppler velocimeters

Basic forms of the optical systems of laser Doppler velocimeters with supression of the additive noise component in the output signal are investigated by the Jones matrix method. The expressions for the resulting Doppler signal, taking into account the parameters and orientation of phase elements and the receiving polarization analyser, have been obtained and analysed. Experimental results are given.