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Surajit Basak Prosanta Biswas Surajit Patra Himadri Roy Manas Kumar Mondal 《矿物冶金与材料学报》2021,28(7):1174-1185
A near eutectic Al?12.6Si alloy was developed with 0.0wt%, 2.0wt%, 4.0wt%, and 6.0wt% Al?5Ti?1B master alloy. The microstructural morphology, hardness, tensile strength, elongation, and fracture behaviour of the alloys were studied. The unmodified Al?12.6Si alloy has an irregular needle and plate-like eutectic silicon (ESi) and coarse polygonal primary silicon (PSi) particles in the matrix-like α-Al phase. The PSi, ESi, and α-Al morphology and volume fraction were changed due to the addition of the Al?5Ti?1B master alloy. The hardness, UTS, and elongation improved due to the microstructural modification. Nano-sized in-situ Al3Ti particles and ex-situ TiB2 particles caused the microstructural modification. The fracture images of the developed alloys exhibit a ductile and brittle mode of fracture at the same time. The Al?5Ti?1B modified alloys have a more ductile mode of fracture and more dimples compared to the unmodified alloy. 相似文献
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Karhadkar SS Bova GS Abdallah N Dhara S Gardner D Maitra A Isaacs JT Berman DM Beachy PA 《Nature》2004,431(7009):707-712
Metastatic cancers adopt certain properties of normal cells in developing or regenerating organs, such as the ability to proliferate and alter tissue organization. We find here that activity of the Hedgehog (Hh) signalling pathway, which has essential roles in developmental patterning, is required for regeneration of prostate epithelium, and that continuous pathway activation transforms prostate progenitor cells and renders them tumorigenic. Elevated pathway activity furthermore distinguishes metastatic from localized prostate cancer, and pathway manipulation can modulate invasiveness and metastasis. Pathway activity is triggered in response to endogenous expression of Hh ligands, and is dependent upon the expression of Smoothened, an essential Hh response component that is not expressed in benign prostate epithelial cells. Monitoring and manipulating Hh pathway activity may thus offer significant improvements in diagnosis and treatment of prostate cancers with metastatic potential. 相似文献
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