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Surface modification of γ-Fe2O3 nanoparticles synthesized by a chemically
induced transition has been attempted by adding ZnCl2 during synthesis.
The structure of the modified particles was studied using X-ray diffraction (XRD)
and transmission electron microscopy (TEM). The experimental results showed that ZnFe2O4 grew epitaxially on the γ- Fe2O3 crystallites to form composite nanoparticles with the spinel structure, on which
FeCl3 might be adsorbed. The apparent grain size dc estimated by XRD using the
Scherrer equation was larger rather than smaller than the average particle size measured by TEM.
This paradox can be explained by the effect of absorption in the coating heterolayer.
In hot-dip galvanizing lines, undesirable vibration of
the moving steel strip occurs due to the impingement of the high-speed
turbulence jet, which leads to non-uniformity of zinc thickness, as well as
splash of the liquid zinc. In this paper, the turbulent jet flow field is
firstly numerically obtained using the CFD method. Then, the influence of the turbulent jet
flow on the steel strip is simplified as a harmonic force at the impingement line, and the response of the steel strip is obtained by means
of finite element analysis for different strip lengths, thickness and
pretension forces. Influences of impingement distance, air knife slot
gap and jet pressure, on vibration of the steel strip are also analyzed. The
results will provide theoretical basis for the reduction of steel strip
vibration in continuous hot-dip galvanizing process.