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Magnetorheological finishing fluid (MRFF), as the transfer medium of magnetorheological finishing, is mainly composed of magnetic particles, base carrier fluid, abrasives and additives, etc. The MRFF with stable performance and good polishing effect is an important factor to achieve magnetorheological deterministic finishing. The magnetic particles with low bulk density are stably suspended in the MRFF, while the micro-structure on the outer surface of the magnetic particles can enhance the holding strength of the magnetic chain bundles on the abrasives in magnetorheological finishing. Highly stable MRFF was prepared by combining solvothermal and calcination reactions to produce flower-like Fe3O4 as magnetic particles, and its settling stability and polishing performance were tested. The stability test results showed that the settling ratio of 64.2% for the flower-like-Fe3O4 MRFF was better than that of 14.2% for the spherical Fe3O4. Compared with the spherical-Fe3O4 magnetic chain bundles, the COMSOL Multiphysics finite element simulation results showed that the magnetic chain bundles composed of flower-like Fe3O4 had a stronger holding force under the magnetic field and a 10.37% increase in shear force during the polishing process. The processing results showed that the polishing depth of flower-like Fe3O4 polishing increased with the gradual reduction of polishing gap, and the polishing with flower-like-Fe3O4 MRFF could obtain deeper material removal depth compared with spherical-Fe3O4 MRFF, and the maximum removal depth increased by 41.5% under the same conditions.

We consider an initial-boundary value problem for the one-dimensional equations of compressible isentropic magnetohydrodynamic (MHD) flows. The non-resistive limit of the global solutions with large data is justified. As a by-product, the global well-posedness of the compressible non-resistive MHD equations is established. Moreover, the thickness of the magnetic boundary-layer of the value with is proved, where is the resistivity coefficient. The proofs of these results are based on a full use of the so-called 'effective viscous flux', the material derivative and the structure of the equations.

This paper concerns the asymptotic behavior of the solution to an initial-boundary value problem of the cylindrically symmetric Navier–Stokes equations with large data for compressible heat-conducting ideal fluids, as the shear viscosity μ goes to zero. A suitable corrector function (the so-called boundary-layer type function) is constructed to eliminate the disparity of boundary values. As by-products, the convergence rates of the derivatives in L 2 are obtained and the boundary-layer thickness (BL-thickness) of the value with is shown by an alternative method, compared with the results proved in Jiang and Zhang (2009 SIAM J. Math. Anal. 41 237–68) and Qin et al (2015 Arch. Ration. Mech. Anal. 216 1049–86).