Effects of equal channel angular pressing(ECAP)extrusion on the microstructure,mechanical properties and biodegradability of Mg–2Zn–xGd–0.5Zr(x=0,0.5,1,2 wt%)alloys were studied in this work.Microstructure analysis...Effects of equal channel angular pressing(ECAP)extrusion on the microstructure,mechanical properties and biodegradability of Mg–2Zn–xGd–0.5Zr(x=0,0.5,1,2 wt%)alloys were studied in this work.Microstructure analysis,tensile test at ambient temperature,immersion test and electrochemical test in Hank’s solution were carried out.The results showed that Gd could further enhance the grain refinement during the ECAP extrusion.Both Gd addition and ECAP extrusion could improve the mechanical properties of the alloys,and the extrusion played the dominant role.Minor addition of Gd(0.5–1 wt%)could obviously enhance the corrosion resistance of the alloys.To some extent,ECAP extrusion improved the corrosion resistance of the alloys due to the change of second phases distribution and the refinement of grains.Further increase in extrusion pass was detrimental to the improvement of the corrosion resistance as a result of increment of the grain boundaries.展开更多
文摘噪声环境下图像压缩感知(compressive sensing,CS)重构方法的性能会大幅度下降。在近似消息传递(approximate message passing,AMP)算法的基础上,同时利用结构先验信息和边信息来增强AMP算法对噪声的鲁棒性。利用图像中相似块的低秩特性,在反投影的含噪图像中捕获低秩子空间的结构特征;再将含有确定成分的前期重构图像作为边信息,以实现细节的增强。实验表明,本文算法比原始AMP算法在峰值信噪比(peak signal to noise ratio,PSNR)上平均提高了3.89dB,且获得更加清晰的重构图像;与仅利用低秩特性的AMP算法相比,引入边信息后本文算法在PSNR上获得了0.27dB的增益,同时增强了重构图像的细节。
基金financially supported by the Key Program of China on Biomedical Materials Research and Tissue and Organ Replacement(Nos.2016YFC1101804 and 2016YFC1100604)the Shenyang Key R&D and Technology Transfer Program(No.Z18-0-027)+2 种基金the National Natural Science Foundation of China(No.51801220)the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Effects of equal channel angular pressing(ECAP)extrusion on the microstructure,mechanical properties and biodegradability of Mg–2Zn–xGd–0.5Zr(x=0,0.5,1,2 wt%)alloys were studied in this work.Microstructure analysis,tensile test at ambient temperature,immersion test and electrochemical test in Hank’s solution were carried out.The results showed that Gd could further enhance the grain refinement during the ECAP extrusion.Both Gd addition and ECAP extrusion could improve the mechanical properties of the alloys,and the extrusion played the dominant role.Minor addition of Gd(0.5–1 wt%)could obviously enhance the corrosion resistance of the alloys.To some extent,ECAP extrusion improved the corrosion resistance of the alloys due to the change of second phases distribution and the refinement of grains.Further increase in extrusion pass was detrimental to the improvement of the corrosion resistance as a result of increment of the grain boundaries.
