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A cyclic sector corresponding to blade-disk structure with dovetail connection (1/38 blade-disk) is studied and the finite element (FE) model of this structure is established based on ANSYS software. A revised normal rubbing force model is developed and a pulse force model is established to simulate the local rubbing phenomenon between the blade and elastic casing based on the revised model. The effects of the rubbing under different rotating speeds and penetration depths on the blade vibration response and contact behaviors of dovetail interface are analyzed. The results show that the rubbing will cause amplitude amplification phenomenon when the multiple frequency components are close to the first bending and first torsion natural frequencies. The arch bending of the blade caused by blade-tip rubbing can be identified by evaluating the displacement and stress of the blade in the radial direction ( y-direction). The dynamic stress in the process of rubbing gradually changes from alternation between tension and compression stress to the tension stress with the increasing rotating speed. Maximum contact sliding distance may change dramatically when the rubbing force is greater than the centrifugal force. With the increase of rotating speed, the contact pressure increases under the centrifugal force and its fluctuation under rubbing is smaller at higher rotating speeds.

In this paper, a new rubbing model between a rotating blade and elastic casing is derived based on the law of conservation of energy. In this model, the bending deflection of blade and the casing deformation during rubbing are taken into account. Based on this model, the influences of the penetration depth, casing stiffness, friction coefficient, blade physical dimensions (thickness, width and length) on the quasi-static normal rubbing forces are analyzed. Moreover, the effects of blade types (thin, thick and tapered blades), casing stiffnesses (aluminum and steel casings), penetration depths and rotating speeds on the normal rubbing forces are also evaluated by simulation and experiment. Moreover, by establishing the dynamic model of the blade and casing, the dynamic normal rubbing forces are also calculated under the blade-casing rubbing. The results show that the rubbing model has satisfactory accuracy by comparing simulation with experiment; the linear or nonlinear characteristic of normal rubbing force depends on the stiffnesses of the blade and the casing; the dynamic normal rubbing force is less than the quasi-static normal rubbing force, and both have the same change trend.

The human ZNF300 gene is a member of the KRAB/C2H2 zinc finger gene family, the members of which are known to be involved in various developmental and pathological processes. Here, we show that the ZNF300 gene encodes a 68-kDa nuclear protein that binds DNA in a sequence-specific manner. The ZNF300 DNA binding site, C(t/a)GGGGG(c/g)G, was defined via a random oligonucleotide selection assay, and the DNA binding site was further confirmed by electrophoretic mobility shift assays. A potential ZNF300 binding site was found in the promoter region of the human IL-2Rβ gene. The results of electrophoretic mobility shift assays indicated that ZNF300 bound to the ZNF300 binding site in the IL-2Rβ promoter in vitro. Transient co-transfection assays showed that ZNF300 could activate the IL-2Rβ promoter, and that the activation was abrogated by the mutation of residues in the ZNF300 binding site. Identifying the DNA binding site and characterizing the transcriptional regulation property of ZNF300 would provide critical insights into its potential as a transcriptional regulator.

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