An experimental study with MPIV (micro particle image velocimetry) flow visualization of incompressible liquid flow in a microchannel is presented. Deionized water served as a working medium. The channel was microfabricated in a PMMA substrate using an excimer laser, and was 115 µm deep, 200 µm wide and 24 000 µm long with a hydraulic diameter of about 146 µm. The pressure drop between the inlet and the outlet of the duct as well as mass flow rates were measured and friction factors were calculated for different Reynolds numbers. Data were discussed and compared with those of previous investigations of similar studies. Moreover, time evolutions of the microflow at the middle of the microchannel at Re = 50, 100, 470 and 900 were photographed. Hydrodynamic entry length correlations were found for both laminar and turbulent flow in the present microchannel.

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Magnetic force microscopy was used to image and detect ferritin proteins and the strength of the magnetic signal is discussed, revealing a large workable lift height between the magnetic tip and the ferritin sample.

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