Measurement of the water ﬂow rate in microchannel has been one of the hottest points in the applications of microfluidics, medical, biological, chemical analyses and so on. In this study, the scanning microscale particle image velocimetry (scanning micro-PIV) technique is used for the measurements of water flow rates in a straight microchannel of 200μm width and 60μm depth under the standard flow rates ranging from 2.481μL/min to 8.269μL/min. The main effort of this measurement technique is to obtain three-dimensional velocity distribution on the cross sections of microchannel by measuring velocities of the different fluid layers along the out-of-plane direction in the microchannel, so the water flow rates can be evaluated from the discrete surface integral of velocities on the cross section. At the same time, the three-dimensional velocity fields in the measured microchannel are simulated numerically using the FLUENT software in order to verify the velocity accuracy of measurement results. The results show that the experimental values of flow rates are well consistent to the standard flow rates input by the syringe pump and the compared results between numerical simulation and experiment are consistent fundamentally. This study indicates that the micro-flow rate evaluated from three-dimensional velocity by the scanning micro-PIV technique is a promising method for the micro-flow rate research.
In this work, we propose a method to measure the Mueller matrix of biological tissues rapidly. Firstly, the effect of
biological tissues on the incident light can be represented as absorption, phase retardance and depolarization. This paper
defines four parameters as absorption coefficient, phase retardance coefficient, depolarization proportion and azimuth of
incident light, respectively. Secondly, we decompose the incident light into two parts: one is totally depolarized, the
other is absorbed and its phase is retarded. The two processes are characterized by two corresponding Mueller
submatrixes. Then two Mueller submatrixes are derived based on the relation between the Stokes vectors of incident
light and output light. Moreover, on the basis of a linear combination of the two Mueller submatrixes, we obtain the
Mueller matrix of biological tissues, which contains the unknown parameters. Lastly, we employ the pellicle cell of
magnolia for the sample and acquisition of it's polarization images. Then this paper applies the method to construct
calculation model from the image data. And just 6 intensity measurements are needed to calculate the four parameters.
In recent years, it has been demonstrated that polarization measurement is more informative than intensity measurement.
As a result, acquisition and detection of polarized information is applied widely in various fields such as remote sensing,
medical treatment and soon. However, most detect applications for the polarized information, and linear polarizer is
described as the key device. Therefore, only linear polarized light information can be detected and other polarization is