In synthetic transmit aperture medical ultrasound imaging field,a compressed sensing ultrasound imaging method based on the sparsity in frequency domain is presented in order to reduce huge amount of data and large nu...In synthetic transmit aperture medical ultrasound imaging field,a compressed sensing ultrasound imaging method based on the sparsity in frequency domain is presented in order to reduce huge amount of data and large numbers of receiving channels.First,the sparsity in frequency domain is verified.Then the echo signal is compressively sampled in time-spatial domain based on compressed sensing and the echo signal is reconstructed by solving an optimization problem.Finally the image is made by using the synthetic transmit aperture approach.The experiments based on point target and fetus target are used to verify the proposed method.The MSE,resolution and image quality of reconstructed image and those of original image are compared and analyzed.The results show that only 30%amount of data and 50%of receiving channels were used to implement ultrasound imaging without reducing the quality of image in experiment.The amount of data and the complexity of system are reduced greatly by the proposed method based on compressed sensing.展开更多
Comprehensive Summary,The trifluoromethoxy functional group has received increasing attention in recent years due to its distinctive properties such as good metabolic stability,appropriate lipophilicity and special el...Comprehensive Summary,The trifluoromethoxy functional group has received increasing attention in recent years due to its distinctive properties such as good metabolic stability,appropriate lipophilicity and special electrical properties.Thus,the development of new reagents and new strategies of direct trifluoromethoxylation are attracting the enthusiasm of many fluorine chemical workers.At present,nucleophilic and radical trifluoromethoxylating reagents have made major breakthroughs,greatly promoting the development of trifluoromethoxy chemistry.展开更多
Significant advancements have been achieved in the field of C,C-palladacycles functionalization in recent decades,which have greatly contributed to the synthesis of intricate drug molecules,natural products,innovative...Significant advancements have been achieved in the field of C,C-palladacycles functionalization in recent decades,which have greatly contributed to the synthesis of intricate drug molecules,natural products,innovative materials,and chiral ligands.Additionally,these advancements have led to the establishment of highly efficient and atom-economic synthetic processes.Based on the differences in the C–Pd bonds,C,C-palladacycles can be further classified into several main types:C(aryl),C(alkyl)-,C(aryl),C(aryl)-,C(aryl),C(vinyl)-,and C(alkyl),C(carbonyl)-palladacycles.This minireview will highlight the recent advances in the synthesis of functional molecules through the functionalization of different C,C-palladacycles,and we hope this survey will inspire future strategic developments for C,C-palladacycle catalysts and their synthetic application.展开更多
Stereospecific hydrohalogenation reactions of electron-deficient alkynes, i.e., 2-alkynoic acids, 2-alkynoates, 2-propynamides, 2-propynenitrile, 1-alkynyl phosphonates/phosphine oxides, 1-alkynyl sulfoxides/triflones...Stereospecific hydrohalogenation reactions of electron-deficient alkynes, i.e., 2-alkynoic acids, 2-alkynoates, 2-propynamides, 2-propynenitrile, 1-alkynyl phosphonates/phosphine oxides, 1-alkynyl sulfoxides/triflones, and 1-alkynyl iodonium salts with lithium or sodium halides to afford Z-alkenyl derivatives and their applications in synthesis of important intermediates as well as natural products were reviewed.展开更多
基金supported by Main Direction Program of Knowledge Innovation of Chinese Academy of Sciences(KGCX2-YW-915)the National Natural Science Foundation of China(11204346)
文摘In synthetic transmit aperture medical ultrasound imaging field,a compressed sensing ultrasound imaging method based on the sparsity in frequency domain is presented in order to reduce huge amount of data and large numbers of receiving channels.First,the sparsity in frequency domain is verified.Then the echo signal is compressively sampled in time-spatial domain based on compressed sensing and the echo signal is reconstructed by solving an optimization problem.Finally the image is made by using the synthetic transmit aperture approach.The experiments based on point target and fetus target are used to verify the proposed method.The MSE,resolution and image quality of reconstructed image and those of original image are compared and analyzed.The results show that only 30%amount of data and 50%of receiving channels were used to implement ultrasound imaging without reducing the quality of image in experiment.The amount of data and the complexity of system are reduced greatly by the proposed method based on compressed sensing.
基金supported by the National Key Research and Development Program of China(2021YFF0701700)NFSC(21925105,92156001)+2 种基金the Natural Science Foundation of Tianjin(Grant No.18JCJQJC47000)NCC Fund(NCC2020FH07)the Haihe Laboratory of Sustainable Chemical Transformations,and the Fundamental Research Funds for the Central Universities.
文摘Comprehensive Summary,The trifluoromethoxy functional group has received increasing attention in recent years due to its distinctive properties such as good metabolic stability,appropriate lipophilicity and special electrical properties.Thus,the development of new reagents and new strategies of direct trifluoromethoxylation are attracting the enthusiasm of many fluorine chemical workers.At present,nucleophilic and radical trifluoromethoxylating reagents have made major breakthroughs,greatly promoting the development of trifluoromethoxy chemistry.
基金This work was supported by the National Natural Science Foundation of China(22101296)the State Key Laboratory of Systems Medicine for Cancer(SB23-09,KF2130-93).
文摘Significant advancements have been achieved in the field of C,C-palladacycles functionalization in recent decades,which have greatly contributed to the synthesis of intricate drug molecules,natural products,innovative materials,and chiral ligands.Additionally,these advancements have led to the establishment of highly efficient and atom-economic synthetic processes.Based on the differences in the C–Pd bonds,C,C-palladacycles can be further classified into several main types:C(aryl),C(alkyl)-,C(aryl),C(aryl)-,C(aryl),C(vinyl)-,and C(alkyl),C(carbonyl)-palladacycles.This minireview will highlight the recent advances in the synthesis of functional molecules through the functionalization of different C,C-palladacycles,and we hope this survey will inspire future strategic developments for C,C-palladacycle catalysts and their synthetic application.
基金Project supported by the National Natural Science Foundation of China (No. 9288012-01)Chinese Academy of Sciences
文摘Stereospecific hydrohalogenation reactions of electron-deficient alkynes, i.e., 2-alkynoic acids, 2-alkynoates, 2-propynamides, 2-propynenitrile, 1-alkynyl phosphonates/phosphine oxides, 1-alkynyl sulfoxides/triflones, and 1-alkynyl iodonium salts with lithium or sodium halides to afford Z-alkenyl derivatives and their applications in synthesis of important intermediates as well as natural products were reviewed.
