Font Size: a A A

Research On Robust Video Watermarking Technology Against Geometric Attacks

Posted on:2010-07-21Degree:MasterType:Thesis
Country:ChinaCandidate:J C FeiFull Text:PDF
GTID:2178330338979456Subject:Signal and Information Processing
Abstract/Summary:PDF Full Text Request
It is indispensable for trace detection with high sensitivity and low detectability to concentrate particles or biological particles in a droplet. The concentration methods having been reported are usually consuming time, which limit their applications. Now, it is one of the most active areas in sample pre-treatment to concentrate particles or biological particles in solution.Surface acoustic wave (SAW) devices have been used widely due to their small size, good reliability, being easily processed for signals and so on. A device for concentrating particles or biological particles in a droplet has been invented and fabricated on a1280 YX-LiNbO3 substrate using SAW technology. It is comprised of two diagonal interdigital transducers and two reflectors. Two SAW in opposite directions excited by diagonal interdigital transducers will be radiated into a droplet, which are in their acoustic paths, and concentrate particles or biological particles in the droplet when an amplified RF signal is added on the diagonal interdigital transducers. In the meantime, the characteristics of SAW propagation along piezoelectric substrate have been analyzed. The force per volume of SAW on a droplet and its attenuation characteristics are also deduced and simulated.The concentration experiments with starch solution and rabbit bood cells show that surface acoustic wave excited by diagonal interdigital transducers can concentrate particles or biological particles in a droplet fastly. The gray value in circle center less 1/6 the droplet radius is one fourth that of a droplet without being concentrated. Compared to other concentration methods, the method has advantages such as high effciency, being easily integrated into Lab on a chip and being unaffected by particles property. This work can improve sensitivity and detectability of trance detection in Lab on a chip and immunologic microfluidic system, which has potential application values.
Keywords/Search Tags:Surface acoustic wave, Inerdigital transducer, Concentration
PDF Full Text Request
Related items