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The ω-phase in metastable β-titanium (Ti) alloys attracts great research interests owing to the metastability and the involved microstructural complexity upon straining, while the fundamental understanding on its formation mechanism is still insufficient. In this study, deformation-induced ω-plates have been systematically investigated using Ti-10 wt% Cr metastable β-Ti alloy containing athermal ω-precipitates. It is found that single-variant ω-plates form either along {332}β twin interfaces or in the twin interiors, which closely depends on twin morphologies. For the acicular β-twin, the ω-plate appears in the twin interiors accompanied by high density of parallel straight dislocations, while for the lenticular twin, the ω-plate attaches to the twin interface without the surrounding dense parallel straight dislocations. These unique formation characteristics result from local stress field induced by the twinning itself and the passive transformation of athermal ω-precipitates. It is further revealed that the passive transformation of athermal ω-precipitates dominates the formation of ω-plates inside the acicular twins, while it is the locally preferential twin thickening that promotes the ω-plates to form along the lenticular twin interfaces. These findings provide new insight into deformation-induced ω-phase transformation and the intricate deformation microstructures in metastable β-Ti alloys.

Background：Lymphogenous metastasis, one of the most common dissemination routes for ovarian carcinoma, predicts a poor prognosis and relates to most cancer-related death. Now there were no effective therapy and control methods for ovarian carcinoma. Hence, it is necessary to build an animal model of lymph node metastasis in ovarian cancer to seek for the tools to find effective treatments. Our purpose of this study was to investigate the tumor cell dissemination of ovarian carcinoma to the gradient lymph nodes of nude mice and its possible mechanism.Methods: The mice models of VEGF-D over-expressed were built, and the tumor growth and sentinel lymph nodes were evaluated weekly, while the visible lymph nodes and tumor masses were excised for histological examination using HE examination. Then Evan’s Blue was conducted to observe the unveil lymphatic network. Subsequently, immunohistochemistry (IHC) was performed to check the protein expression of relative genes. Meanwhile, microvessel counting was performed within the tumor tissues and measured using computer assisted morphometric analysis.Results: The over-expression of VEGF-D promoted the tumor growth of ovarian carcinoma, facilitated the hyperplasia of tumor lymphatic and increased the intratumoral lymphatic vessel density. Besides, the up-regulation of VEGF-D induced the expression of MMP-2, which might be the underlying mechanism of the lymph metastasis in ovarian cancer.Conclusion: It was a step-by-step progression from the inoculation of cancer cells to the proliferation of the primary tumors, and then to the lymphatic metastases, in which VEGF-D and MMP-2 played vital roles.

Unlike stress-induced martensitic transformation, deformation twinning as well as dislocation gliding, deformation kinking is an uncommon deformation mechanism in metastable β-titanium (Ti) alloys. In this study, the unique deformation mechanism was reported in Ti-V binary β-Ti alloys for the first time. It was found that a large number of kink bands were distributed in β-grains after cold forging at a strain rate of ~103 s−1. Microstructural characterization manifests that the appearance of kink bands is frequently accompanied by slip bands, whilst dense dislocations are accumulated around the kink bands on a microscopic scale. Such local plastic deformation is quite strong so that the pre-existing athermal ω-precipitates in the initial microstructure is completely destroyed within the kink bands and instead fresh deformation-induced single variant of ω-precipitates is produced. This deformation localization mainly originates from the impediment of dislocation activity caused by both pre-existing athermal ω-precipitates and the intrinsic slip retardation in BCC crystal structures. The deformation kinking is thus suggested to follow a dislocation-based formation mechanism, whilst the resulting Taylor axis of lattice rotation was deduced to be β on basis of extensive crystallographic analysis. These findings enrich fundamental understanding on deformation kinking, and provide helpful information for utilizing the unique deformation mechanism to tune mechanical properties of β-Ti alloys.

As a governing equation of wave propagation in a nonlinear, dispersive and dissipative media, KdV–Burgers type equation has received great attention. In this paper, the dynamical behavior of the generalized KdV–Burgers equation under a periodic perturbation is investigated numerically in detail. It is shown that dynamical chaos can occur when we choose appropriately systematic parameters and initial conditions. Abundant bifurcation structures and different routes to chaos such as period-doubling and inverse period-doubling cascades, intermittent bifurcation and crisis, are found by applying bifurcation diagrams, the Poincaré maps and phase portraits. To characterize chaotic behavior of this system, the spectrum of Lyapunov exponent and Lyapunov dimension of the attractor are also employed.