Tailoring the Ti coordination states in titanosilicate zeolites to simultaneously improve feedstock conversion and maximize the target product selectivity remains a challenge in the pursuit of high-performance catalys...Tailoring the Ti coordination states in titanosilicate zeolites to simultaneously improve feedstock conversion and maximize the target product selectivity remains a challenge in the pursuit of high-performance catalysts for selective oxidation reactions.Herein,we provide a facile strategy to synthesize hierarchical anatase-free TS-1(MFI-type)zeolites with tetrahedrally coordinated(TiO_(4))and octahedrally coordinated Ti species(TiO_(6)).The TiO_(4)species provide high epoxide selectivity,while the TiO_(6)species afford improved alkene conversion.This strategy is achieved by synergistically using an L-lysine-assisted approach and a two-step crystallization;the two-step crystallization approach prevents the formation of anatase TiO_(2),while L-lysine stabilizes the TiO_(6)species and ensures efficient incorporation of TiO_(6)into the anatase-free TS-1 zeolites.Compared with their conventional counterparts,which only contain TiO_(4)species,the as-prepared TS-1 zeolites(Si/Ti=36.9)result in a higher 1-hexene conversion(33%),higher TON value(153),and comparable epoxide selectivity(95%).This synthetic strategy provides avenues to tailor the amount and distribution of Ti species in titanosilicate zeolites to achieve high catalytic performances in various processes.展开更多
Coarse-to-fine pyramid and scale space are two important image structures in the realm of image matching.However,the advantage of coarse-to-fine pyramid is neglected as the pyramid structure is usually constructed wit...Coarse-to-fine pyramid and scale space are two important image structures in the realm of image matching.However,the advantage of coarse-to-fine pyramid is neglected as the pyramid structure is usually constructed with the down sampling method in scale space.In addition,the importance of each lattice is different for one single image.Based on the analyses above,the new multi-pyramid(M-P)image spatial structure is constructed.First,coarse-to-fine pyramid is constructed by partitioning the original image into increasingly finer lattices,and the number of interest points is also adopted to be each lattice’s non-normalized weight on each pyramid level.Second,the scale space of each lattice on each pyramid level is generated with the classic Gaussian kernel.Third,the descriptors of each lattice are generated by regarding the stability of scale space as the description of image.Moreover,the parallel version of M-P algorithm is also presented to accelerate the speed of computation.Finally,the comprehensive experimental results reveal that our multi-pyramid structure which is constructed by the combination of coarse-to-fine spatial pyramid and scale space can generate more effective features,compared with the other related methods.展开更多
文摘Tailoring the Ti coordination states in titanosilicate zeolites to simultaneously improve feedstock conversion and maximize the target product selectivity remains a challenge in the pursuit of high-performance catalysts for selective oxidation reactions.Herein,we provide a facile strategy to synthesize hierarchical anatase-free TS-1(MFI-type)zeolites with tetrahedrally coordinated(TiO_(4))and octahedrally coordinated Ti species(TiO_(6)).The TiO_(4)species provide high epoxide selectivity,while the TiO_(6)species afford improved alkene conversion.This strategy is achieved by synergistically using an L-lysine-assisted approach and a two-step crystallization;the two-step crystallization approach prevents the formation of anatase TiO_(2),while L-lysine stabilizes the TiO_(6)species and ensures efficient incorporation of TiO_(6)into the anatase-free TS-1 zeolites.Compared with their conventional counterparts,which only contain TiO_(4)species,the as-prepared TS-1 zeolites(Si/Ti=36.9)result in a higher 1-hexene conversion(33%),higher TON value(153),and comparable epoxide selectivity(95%).This synthetic strategy provides avenues to tailor the amount and distribution of Ti species in titanosilicate zeolites to achieve high catalytic performances in various processes.
文摘Coarse-to-fine pyramid and scale space are two important image structures in the realm of image matching.However,the advantage of coarse-to-fine pyramid is neglected as the pyramid structure is usually constructed with the down sampling method in scale space.In addition,the importance of each lattice is different for one single image.Based on the analyses above,the new multi-pyramid(M-P)image spatial structure is constructed.First,coarse-to-fine pyramid is constructed by partitioning the original image into increasingly finer lattices,and the number of interest points is also adopted to be each lattice’s non-normalized weight on each pyramid level.Second,the scale space of each lattice on each pyramid level is generated with the classic Gaussian kernel.Third,the descriptors of each lattice are generated by regarding the stability of scale space as the description of image.Moreover,the parallel version of M-P algorithm is also presented to accelerate the speed of computation.Finally,the comprehensive experimental results reveal that our multi-pyramid structure which is constructed by the combination of coarse-to-fine spatial pyramid and scale space can generate more effective features,compared with the other related methods.
基金supported by the National Natural Science Foundation of China(32271545 and 31972030)Major Program of Haihe Laboratory of Synthetic Biology(22HHSWSS00016 and 22HHSWSS00003)+2 种基金Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project(TSBICIP-KJGG-008-03 and TSBICIP-PTJJ-007-10)Youth Promotion Association of Chinese Academy of Sciences(CAS)(2021176)CAS Project for Young Scientists in Basic Research(YSBR-072)。
