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Abstract: ZrO2 nanoparticles was uniformly co-deposited into a nickel matrix by electroplating of nickel from a Watts bath containing particles in suspension which were monodispersed with dispersant under DC electrodeposition condition. It was found that morphology, orientation and hardness of the nanocomposite coatings with monodispersed ZrO2 nanoparticles had lots of difference from the nanocomposite coatings with agglomerated ZrO2 nanoparticles and pure nickel coatings. Especially, the result of hardness showed that only a very low volume percent (less than 1wt.%) of monodispered ZrO2 nanoparticles in Ni–ZrO2 nanocomposite coatings would result in higher hardness of the coatings. The hardness of Ni–ZrO2 nanocomposite coatings with monodispersed and agglomerated ZrO2 nanoparticles were 529 and 393HV, respectively. The hardness value of the former composite coatings was over 1.3 times higher than that of the later. All these composite coatings were two–three times higher than that of pure nickel plating (207HV) prepared under the same condition. The strengthening mechanisms of the Ni–ZrO2 nanocomposite coatings based on a combination of grain refinement strengthening from nickel matrix grain refining and dispersion strengthening from dispersion state of ZrO2 nanoparticles in the coatings. [Copyright &y& Elsevier]

In this paper, laser interference induced dielectrophoresis (LIIDEP) was presented for cell manipulation and three-dimensional array assembly. Two-beam and three-beam interference systems were built to manipulate yeast cells in deionized water. When the laser power was 60 μW and the sinusoidal AC signal was 6 V at 10 kHz, the two-beam interference pattern manipulated the cells into a single-row array distribution. For three-beam interference, when the laser power was 70 μW and the frequency was 4.5 kHz, the voltage of 2.5 V enabled each spot to control one cell, and 7.5 V enabled many spots to control multiple cells. When the cell concentration was 2 × 107 cells/mL and the electrical signal was 8 V and 4.5 kHz, the cells were assembled into a three-dimensional columnar array. The feature size of laser interference pattern was adjusted to microscale and maintained sharp boundaries, which effectively improved the manipulation accuracy. Compared to the projector or laser as the ODEP light source, LIIDEP has the advantages of high manipulation resolution, good contrast and large dielectrophoretic force. This work provides an effective way for high resolution three-dimensional array manipulation and assembly of a large number of living cells on the microscale in liquid environments. • The interference pattern effectively improves the precision of cells operation. • Two-beam interference pattern manipulated cells into a single-row array distribution. • Each spot of the three-beam interference pattern controls single or multiple cells. • The cells can be quickly assembled into a 3D columnar array. [ABSTRACT FROM AUTHOR]