Nonintrusive measurements of mixture concentration fields by analyzing diffraction image patterns (point spread function) of nanoparticles

作者：Park Jae Sung; Kihm Kenneth D^*; Lee Joon Sik

来源：Experiments in Fluids, 2010, 49(1): 183-191.

DOI：10.1007/s00348-010-0831-2

The diffraction image patterns of small particles are referred to as their point spread PSF); these patterns vary distinctively with the refractive index (RI) of a transparent test medium when the particles are imaged through the medium. The RI correlates directly with the mixture concentration, so proper inversion of measured PSFs can provide full-field information on the mixture concentration field. In this study, fluorescent nanoparticles of 500 nm diameter are fixed on a glass surface by means of evaporative self-assembly, and the time-varying test mixture is placed in front of the glass surface. The time-varying and full-field PSF distributions are imaged and digitally analyzed to determine the local RI values as well as the local mixture concentrations. Both immiscible water/oil mixture and miscible water/glycerol mixture are imaged. The present method shows an RI measurement to have an uncertainty of +/- 5 x 10(-3) RIU and the mixture concentration measurements to have uncertainty of approximately 4%.

• 出版日期2010-7