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The superhydrophobic surface can change the friction property of the material, reduce the adhesion of the friction interface, and produce a certain slip, thereby reducing the friction coefficient. The laser has high energy, high density, and is especially suitable for the surface treatment of materials. The laser surface texturing is a good way to construct superhydrophobic surfaces. The experiment uses a nanosecond pulse laser to construct the groove texture on the nickel surface. The contact area between the air and the droplets retained on the rough surface is increased, effectively preventing the water droplets from entering the gully of the surface microstructure, reducing the water droplets and the solid surface. The contact area ultimately makes the surface exhibit excellent superhydrophobicity. A superhydrophobic nickel surface having an apparent contact angle of water (ACAW) of 160° and a sliding angle (SA) of less than 10° was prepared. The MM-W1B vertical universal friction and wear tester was used to test the groove texture samples with different depths. The surface texture can capture the wear debris generated by the wear and store the lubricant, which is beneficial to the formation of fluid dynamic pressure lubrication and improve the load. The friction coefficient is reduced from 0.65 of the unprocessed surfaces to 0.25 after the texturing, and the friction performance is greatly improved.

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The Bulk Superconductivity Group at the University of Cambridge is currently investigating the use of high temperature superconductors in wire and bulk form to increase the electrical and magnetic loading of an axial gap, trapped flux-type superconducting electric machine. The use of superconducting materials in electric machines can lead to increases in efficiency, as well as power density, which results in reductions in both the size and weight of the machine. In this paper, the authors present a method to compute the field in such an electric machine generated by an array of fully magnetized bulk superconductors. Analytical expressions are derived for the field that would exist in the coil region of the motor, which will act as a powerful tool for carrying out parametric analysis of the motor's design and performance.

Friction is one of the main causes of mechanical component failure and material waste. It is known from the friction theory that changing the roughness of the surface of the material can change the friction property of the material. Laser surface texturing is a good method for constructing a rough surface. In the experiment, the texture of the circular pits with different areal densities was constructed on the nickel surface. The coefficient of friction of the circular pit under the water-lubricated friction condition was kept at about 0.17, while the untreated metal nickel under the same conditions exceeds 0.65. The circular pit texture improves the frictional properties of the nickel surface.