Morphological evolution of the solid-liquid interface near grain boundaries has been studied during directional solidification of succinonitrile-based transparent alloys (SCN-0.9wt%DCB). Experimental results show that...Morphological evolution of the solid-liquid interface near grain boundaries has been studied during directional solidification of succinonitrile-based transparent alloys (SCN-0.9wt%DCB). Experimental results show that the grain boundary provides the starting point of morphological instability of the solid-liquid interface. The initial perturbation near the grain boundary is significantly larger than other perturbations on the interface. The initial shape of the interface and the competition between the thermal direction and preferred crystalline orientations determine the subsequent growth pattern selections. The temporal variations of the curvature radius of cell/ridge tips near the grain boundary have also been studied when the instability occurs. This process is divided into three parts. As the pulling velocity increases, dendrites at the grain boundary grow in two different directions to form a bicrystal microstructure. Side branches on either side of the dendrite exhibit different growth patterns.展开更多
A series of novel polymethoxyflavone Marmich base derivatives 1--8 was synthesized by Mannich reaction of 5-hydroxy-3,7,3＇,4＇-tetramethoxyflavone 9 with various secondary aliphatic amines and formaldehyde. Their ace...A series of novel polymethoxyflavone Marmich base derivatives 1--8 was synthesized by Mannich reaction of 5-hydroxy-3,7,3＇,4＇-tetramethoxyflavone 9 with various secondary aliphatic amines and formaldehyde. Their acetylcholmesterase（AChE） inhibitory activities were evaluated. The results showed that most of them exhibited AChE inhibitory activity and especially piperidin-l-yl methyl substituent derivative 5（IC50=0.238 μmol/L） demon- strated stronger activity comparable with the positive control, neoeserinemethyl sulfate（IC50=1.39 μmol/L）, which is worthy of further development as an agent for Alzheimer＇s disease treatment.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.61078057 and 51172183)NPU Foundation for Fundamental Research (Grant Nos.NPU-FFR-JC201048 and JC201155)+1 种基金the Science & Technology Program of Shanghai Maritime University (Grant No.20110054)the Project of the Excellent Youth of Shanghai (WANG CaiFang)
文摘Morphological evolution of the solid-liquid interface near grain boundaries has been studied during directional solidification of succinonitrile-based transparent alloys (SCN-0.9wt%DCB). Experimental results show that the grain boundary provides the starting point of morphological instability of the solid-liquid interface. The initial perturbation near the grain boundary is significantly larger than other perturbations on the interface. The initial shape of the interface and the competition between the thermal direction and preferred crystalline orientations determine the subsequent growth pattern selections. The temporal variations of the curvature radius of cell/ridge tips near the grain boundary have also been studied when the instability occurs. This process is divided into three parts. As the pulling velocity increases, dendrites at the grain boundary grow in two different directions to form a bicrystal microstructure. Side branches on either side of the dendrite exhibit different growth patterns.
基金Supported by the National Natural Science Foundation of China（No.J1210040） and the Hunan Provincial Natural Science Foundation, China（No. 14JJ2048）.
文摘A series of novel polymethoxyflavone Marmich base derivatives 1--8 was synthesized by Mannich reaction of 5-hydroxy-3,7,3＇,4＇-tetramethoxyflavone 9 with various secondary aliphatic amines and formaldehyde. Their acetylcholmesterase（AChE） inhibitory activities were evaluated. The results showed that most of them exhibited AChE inhibitory activity and especially piperidin-l-yl methyl substituent derivative 5（IC50=0.238 μmol/L） demon- strated stronger activity comparable with the positive control, neoeserinemethyl sulfate（IC50=1.39 μmol/L）, which is worthy of further development as an agent for Alzheimer＇s disease treatment.
