Crystallization,while a common process in nature,remains one of the most mysterious phenomena.Understanding its physical mechanisms is essential for obtaining high-quality crystals.Typically,crystals grown by thermal ...Crystallization,while a common process in nature,remains one of the most mysterious phenomena.Understanding its physical mechanisms is essential for obtaining high-quality crystals.Typically,crystals grown by thermal evaporation or sublimation nucleate the substrate facing the evaporation source.Here,a novel vapor micro-turbulence mass transport mechanism in the growth process of ultrathin BiOCl single crystals has been revealed.In this mechanism,the precursor vapor bypasses the solid substrate,forming micro-turbulent vaporizing flows to nucleate on the surface of the substrate facing away from the evaporation source.Considering nucleation kinetics,fast shear flows are known to cause secondary nucleation,increasing nucleation quantity while decreasing the final size of the crystals.Thus,the nucleation and growth process of BiOCl crystals are controlled by adjusting the micro-turbulence intensity to reduce shear flow energy and dilate phase distribution,resulting in BiOCl crystals with uniform distribution and regular shape.Subsequent structural and morphological characterization confirms the high crystallization quality of the obtained crystals,and the performance of the constructed solar-blind photodetectors is comparable to that of similar devices.These findings contribute to a deeper understanding of vapor mass transport and crystal growth techniques and may be useful for applications related to metal oxide crystals.展开更多
Railways within the city carry the historical memory of urban development and are important industrial heritage resources.However,with urban development and changes in transportation functions,railways lose their orig...Railways within the city carry the historical memory of urban development and are important industrial heritage resources.However,with urban development and changes in transportation functions,railways lose their original application value and are gradually left unused or even abandoned,affecting the vitality of the region.Taking the space around Xihuangcun Railway Station as the research object,the public activity space on both sides of the railway is reshaped through five strategies:function revitalization,traffic revitalization,heritage revitalization,spatial revitalization,and landscape revitalization,and the grey area of the city is transformed into a vibrant development zone of the city.展开更多
Theoretical consideration was conducted on a relation between pore diameter and interfacialarea between pores and fibers when pores uniforinly distribute in C/C composites. It was shownthat bonding at the fiber/matrix...Theoretical consideration was conducted on a relation between pore diameter and interfacialarea between pores and fibers when pores uniforinly distribute in C/C composites. It was shownthat bonding at the fiber/matrix interface apparently decreased with decreasing a pore diameter,and consequently a new idea of microspace modification concept was proposed for controllingfracture behavior of C/C composites. Four types of C/C composites with various pore structureswere fabricated by hot-pressing, and their fracture behavior was investigated by three pointbending tests. The fracture behavior of the C/C composites was changed from brittle one topseudo ductile one with decreasing the pore diameter. This result supported the validity of themicrospace modification concept proposed in this paper.展开更多
基金financially supported by Jiangsu Funding Program for Excellent Postdoctoral Talent(Nos.2023ZB695 and 2023ZB167)China Postdoctoral Science Foundation(Nos.2023M742557 and 2023M742561)+2 种基金the National Natural Science Foundation of China(No.52372055)the Basic Research Development Program of Suzhou(No.SJC2023004)Jiangsu Independent Innovation Fund Project of Agricultural Science and Technology(No.CX(21)3163)。
文摘Crystallization,while a common process in nature,remains one of the most mysterious phenomena.Understanding its physical mechanisms is essential for obtaining high-quality crystals.Typically,crystals grown by thermal evaporation or sublimation nucleate the substrate facing the evaporation source.Here,a novel vapor micro-turbulence mass transport mechanism in the growth process of ultrathin BiOCl single crystals has been revealed.In this mechanism,the precursor vapor bypasses the solid substrate,forming micro-turbulent vaporizing flows to nucleate on the surface of the substrate facing away from the evaporation source.Considering nucleation kinetics,fast shear flows are known to cause secondary nucleation,increasing nucleation quantity while decreasing the final size of the crystals.Thus,the nucleation and growth process of BiOCl crystals are controlled by adjusting the micro-turbulence intensity to reduce shear flow energy and dilate phase distribution,resulting in BiOCl crystals with uniform distribution and regular shape.Subsequent structural and morphological characterization confirms the high crystallization quality of the obtained crystals,and the performance of the constructed solar-blind photodetectors is comparable to that of similar devices.These findings contribute to a deeper understanding of vapor mass transport and crystal growth techniques and may be useful for applications related to metal oxide crystals.
文摘Railways within the city carry the historical memory of urban development and are important industrial heritage resources.However,with urban development and changes in transportation functions,railways lose their original application value and are gradually left unused or even abandoned,affecting the vitality of the region.Taking the space around Xihuangcun Railway Station as the research object,the public activity space on both sides of the railway is reshaped through five strategies:function revitalization,traffic revitalization,heritage revitalization,spatial revitalization,and landscape revitalization,and the grey area of the city is transformed into a vibrant development zone of the city.
文摘Theoretical consideration was conducted on a relation between pore diameter and interfacialarea between pores and fibers when pores uniforinly distribute in C/C composites. It was shownthat bonding at the fiber/matrix interface apparently decreased with decreasing a pore diameter,and consequently a new idea of microspace modification concept was proposed for controllingfracture behavior of C/C composites. Four types of C/C composites with various pore structureswere fabricated by hot-pressing, and their fracture behavior was investigated by three pointbending tests. The fracture behavior of the C/C composites was changed from brittle one topseudo ductile one with decreasing the pore diameter. This result supported the validity of themicrospace modification concept proposed in this paper.
