In this study the contrast analysis was made between the alloys of Mg-Zn-Zr and Mg-Zn-Zr with 0.94% (mass fraction) of Y by metallographic examination, mechanical property testing, X-ray diffraction, scanning electron...In this study the contrast analysis was made between the alloys of Mg-Zn-Zr and Mg-Zn-Zr with 0.94% (mass fraction) of Y by metallographic examination, mechanical property testing, X-ray diffraction, scanning electron microscope, transmission electron microscope and electron probe. The results show that the addition of Y to the testing alloy can make the grains fine and improve the alloy′s metallographic structures. The element Y will gather among the grain boundaries besides Zn and the Y-Zn phase can form under that condition. In the grains there is only a small amount of Y in the forms of solid solution with the matrix and the Mg-Y phase with Mg. To add 0.94% of Y to the alloy will greatly improve the tensile strength of the alloy in the hot extruding test because the most important thing is that Y acted as an alterant so it can improve the alloy′s metallographic structures. Meanwhile, under the condition of hot extruding, a great amount of fine dispersive particles of Y-Zn and Mg-Y phases are formed so that the alloy becomes strengthened. Furthermore, the strengthening is because of the sub-grains resulted from plastic deformation.展开更多
Two new furan fragment isomerized limonoids, meliazedalides A and B(compounds 1 and 2), were isolated from the fruits of Melia azedarach Linn.. Their chemical structures were elucidated on the basis of HR-ESI-MS and 1...Two new furan fragment isomerized limonoids, meliazedalides A and B(compounds 1 and 2), were isolated from the fruits of Melia azedarach Linn.. Their chemical structures were elucidated on the basis of HR-ESI-MS and 1D and 2D NMR data, which belonged to nimbolinin-and trichilin-class, respectively. Compound 2 exhibited weak inhibitory effect on NO production in lipopolysaccharide(LPS)-activated RAW 264.7 macrophages with IC_(50) being 37.41 μmol·L^(–1).展开更多
文摘In this study the contrast analysis was made between the alloys of Mg-Zn-Zr and Mg-Zn-Zr with 0.94% (mass fraction) of Y by metallographic examination, mechanical property testing, X-ray diffraction, scanning electron microscope, transmission electron microscope and electron probe. The results show that the addition of Y to the testing alloy can make the grains fine and improve the alloy′s metallographic structures. The element Y will gather among the grain boundaries besides Zn and the Y-Zn phase can form under that condition. In the grains there is only a small amount of Y in the forms of solid solution with the matrix and the Mg-Y phase with Mg. To add 0.94% of Y to the alloy will greatly improve the tensile strength of the alloy in the hot extruding test because the most important thing is that Y acted as an alterant so it can improve the alloy′s metallographic structures. Meanwhile, under the condition of hot extruding, a great amount of fine dispersive particles of Y-Zn and Mg-Y phases are formed so that the alloy becomes strengthened. Furthermore, the strengthening is because of the sub-grains resulted from plastic deformation.
基金supported by the National Natural Science Foundation of China(No.81573550)the Outstanding Youth Fund of the Basic Research Program of Jiangsu Province(BK20160077)
文摘Two new furan fragment isomerized limonoids, meliazedalides A and B(compounds 1 and 2), were isolated from the fruits of Melia azedarach Linn.. Their chemical structures were elucidated on the basis of HR-ESI-MS and 1D and 2D NMR data, which belonged to nimbolinin-and trichilin-class, respectively. Compound 2 exhibited weak inhibitory effect on NO production in lipopolysaccharide(LPS)-activated RAW 264.7 macrophages with IC_(50) being 37.41 μmol·L^(–1).
基金This work was financially supported by the start-up funding from Soochow University,Peking University,and Thousand Youth Talent Program,the National Natural Science Foundation of China (No.21571135),and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).
