Donor-acceptor(D-A)compounds are particularly important in optoelectronic and biological applications.However,they are normally synthesized in the presence of transition metal catalysts.Herein,we report a metal-free m...Donor-acceptor(D-A)compounds are particularly important in optoelectronic and biological applications.However,they are normally synthesized in the presence of transition metal catalysts.Herein,we report a metal-free method by a complexmediated nucleophilic aromatic substitution of aryl nitriles with amines.The method can lead to rich D-A type aggregation-induced emission luminogens(AIEgens)with tunable properties.They emit from deep-blue to yellow-green and possess high photoluminescence quantum yields up to 70.5%in the aggregate state.Interestingly,the suppression of intramolecular flapping is proved to play an indispensable role in the AIE behavior,which is different from the mechanism met in other AIEgens.Moreover,the biocompatible AIEgens possess specific staining of lipid droplets in HeLa cells and the superiority of identifying fatty liver over traditional Oil Red O staining is exhibited.展开更多
The fracture behavior at high temperatures of the Ti−22Al−26Nb alloy,which features duplex lamellar,bimodal,and Widmanstätten structures,was studied.Samples of the alloy were prepared through compression deformat...The fracture behavior at high temperatures of the Ti−22Al−26Nb alloy,which features duplex lamellar,bimodal,and Widmanstätten structures,was studied.Samples of the alloy were prepared through compression deformation in the trans-phase region followed by subsequent heat treatment.The results indicate that at 650℃,the fracture toughness of the Ti−22Al−26Nb alloy is increased by 41.7%compared to that with original microstructures.The content of the B2 phase significantly influences the inherent fracture toughness of the material,while the morphology and distribution of the precipitated phases primarily affect the tortuosity of the crack propagation path.Among the microstructural features,the morphology and geometric orientation of the lamellae most significantly impact the crack path;consequently,the Widmanstätten structure exhibits the most tortuous fracture path.Additionally,a predictive model for fracture toughness is developed,which effectively predicts the fracture toughness of Ti−22Al−26Nb alloys with various microstructures at 650℃.展开更多
基金supported by the National Natural Science Foundation of China(22275072 and 62105184)the Natural Science Foundation of Guangdong Province(2020A1515010622)+1 种基金the Project of Science and Technology of Guangzhou(2024A04J3712)the Teli Young Scholar Program of Beijing Institute of Technology.
文摘Donor-acceptor(D-A)compounds are particularly important in optoelectronic and biological applications.However,they are normally synthesized in the presence of transition metal catalysts.Herein,we report a metal-free method by a complexmediated nucleophilic aromatic substitution of aryl nitriles with amines.The method can lead to rich D-A type aggregation-induced emission luminogens(AIEgens)with tunable properties.They emit from deep-blue to yellow-green and possess high photoluminescence quantum yields up to 70.5%in the aggregate state.Interestingly,the suppression of intramolecular flapping is proved to play an indispensable role in the AIE behavior,which is different from the mechanism met in other AIEgens.Moreover,the biocompatible AIEgens possess specific staining of lipid droplets in HeLa cells and the superiority of identifying fatty liver over traditional Oil Red O staining is exhibited.
基金financially supported by the National Natural Science Foundation of China(Nos.51975175,51875158)。
文摘The fracture behavior at high temperatures of the Ti−22Al−26Nb alloy,which features duplex lamellar,bimodal,and Widmanstätten structures,was studied.Samples of the alloy were prepared through compression deformation in the trans-phase region followed by subsequent heat treatment.The results indicate that at 650℃,the fracture toughness of the Ti−22Al−26Nb alloy is increased by 41.7%compared to that with original microstructures.The content of the B2 phase significantly influences the inherent fracture toughness of the material,while the morphology and distribution of the precipitated phases primarily affect the tortuosity of the crack propagation path.Among the microstructural features,the morphology and geometric orientation of the lamellae most significantly impact the crack path;consequently,the Widmanstätten structure exhibits the most tortuous fracture path.Additionally,a predictive model for fracture toughness is developed,which effectively predicts the fracture toughness of Ti−22Al−26Nb alloys with various microstructures at 650℃.
