In the western and central Pacific Ocean,upper strata waters exhibit highly dynamic oceanographic features under ENSO variability.This has been proved to be responsible for the dynamic change of both abundance and zon...In the western and central Pacific Ocean,upper strata waters exhibit highly dynamic oceanographic features under ENSO variability.This has been proved to be responsible for the dynamic change of both abundance and zonal distribution of skipjack tuna(Katsuwonus pelamis).Although causality has been suggested by researchers using physical-biological interaction models,cumulative evidence needs to be obtained and the tenability of assertion needs to be tested from an ecological habitat perspective,based on fisheries data.For purse seine fishery,the use of catch per unit effort(CPUE)as an indication of the abundance is confusing because of technical improvements over the whole exploitation history and unbalanced individual fishing characteristic of vessels.It is particularly interesting to discriminate between habitat characteristics in comparative scenarios of CPUE application.This study identified habitat traits based on a series of oceanographic factors from a global ocean reanalysis model.A comparison was conducted between two habitat models based on unprocessed purse seine CPUE and standardized CPUE considering fishing characteristics.The results suggest that standardized CPUE could model the regular zonal shift of habitat compatible with the observed fishing efforts transfer,and achieved better prediction capacity than unprocessed CPUE.Furthermore,the habitat of skipjack tuna was also characterized and linked with surface and subsurface thermal environment,ocean current,dissolved oxygen,biotic environment,and ENSO variability.The monthly-averaged habitat suitable index,derived from the optimal habitat model prediction,showed a significant linear relationship with the southern oscillation index,which suggested that El Ni?o episodes eventually provide more preferable habitat for skipjack tuna under ENSO variability.展开更多
The robust stability of uncertain neutral systems with mixed time-varying delays is investigated in this paper. The uncertainties under consideration are norm-bounded and time-varying. Based on the Lyapunov stability ...The robust stability of uncertain neutral systems with mixed time-varying delays is investigated in this paper. The uncertainties under consideration are norm-bounded and time-varying. Based on the Lyapunov stability theory, a delay-dependent stability criterion is derived and given in the form of a linear matrix inequality （LMI）. Finally, a numerical example is given to illustrate significant improvement over some existing results.展开更多
Phase-transfer-catalyzed intramolecular cyclization reaction of forming benzo[b]furan and 3-methyleneisoin- doline-1-one derivatives has been developed. The cyclization reaction of propargylic carbonates was also de- ...Phase-transfer-catalyzed intramolecular cyclization reaction of forming benzo[b]furan and 3-methyleneisoin- doline-1-one derivatives has been developed. The cyclization reaction of propargylic carbonates was also de- scribed under metal-free condition and the reaction was reported by Pd and Ni before. The reaction condi- tions and the scope of the process are examined. The catalysts are cheap and environmentally friendly and the substrates are readily available and the procedure is simple, rapid, and general. The development of C-O and C-N bond formation processes via an overall structural isomerization represents the most atom-eco- nomical approach.展开更多
This paper presents an algorithm to solve the problem of Photo-Response Non-Uniformity(PRNU)noise facing stabilized video.The stabilized video undergoes in-camera processing like rolling shutter correction.Thus,misali...This paper presents an algorithm to solve the problem of Photo-Response Non-Uniformity(PRNU)noise facing stabilized video.The stabilized video undergoes in-camera processing like rolling shutter correction.Thus,misalignment exists between the PRNU noises in the adjacent frames owing to the global and local frame registration performed by the in-camera processing.The misalignment makes the reference PRNU noise and the test PRNU noise unable to extract and match accurately.We design a computing method of maximum likelihood estimation algorithm for extracting the PRNU noise from stabilized video frames.Besides,unlike most prior arts tending to match the PRNU noise in whole frame,we propose a new patch-based matching strategy,aiming at reducing the influence from misalignment of frame the PRNU noise.After extracting the reference PRNU noise and the test PRNU noise,this paper adopts the reference and the test PRNU overlapping patch-based matching.It is different from the traditional matching method.This paper conducts different experiments on 224 stabilized videos taken by 13 smartphones in the VISION database.The area under curve of the algorithm proposed in this paper is 0.841,which is significantly higher than 0.805 of the whole frame matching in the traditional algorithm.Experimental results show good performance and effectiveness the proposed strategy by comparing with the prior arts.展开更多
While heteroatom doping serves as a powerful strategy for devising novel polycyclic aromatic hydrocarbons(PAHs), the further fine-tuning of optoelectronic properties via the precisely altering of doping patterns remai...While heteroatom doping serves as a powerful strategy for devising novel polycyclic aromatic hydrocarbons(PAHs), the further fine-tuning of optoelectronic properties via the precisely altering of doping patterns remains a challenge. Herein, by changing the doping positions of heteroatoms in a diindenopyrene skeleton, we report two isomeric boron, sulfur-embedded PAHs, named Anti-B_(2)S_(2) and Syn-B_(2)S_(2), as electron transporting semiconductors. Detailed structure-property relationship studies revealed that the varied heteroatom positions not only change their physicochemical properties, but also largely affect their solid-state packing modes and Lewis base-triggered photophysical responses. With their low-lying frontier molecular orbital levels, n-type characteristics with electron mobilities up to 1.5 × 10^(-3)cm^(2)V^(-1)s^(-1)were achieved in solution-processed organic field-effect transistors. Our work revealed the critical role of controlling heteroatom doping patterns for designing advanced PAHs.展开更多
Biomass carbon and small redox biomolecules are attractive materials for green,sustainable energy storage devices owing to their environmentally friendly,low-cost,scalable,and novel sources.However,most devices manufa...Biomass carbon and small redox biomolecules are attractive materials for green,sustainable energy storage devices owing to their environmentally friendly,low-cost,scalable,and novel sources.However,most devices manufactured using these materials have low specific capacitance,poor cycle stability,short lifetime,complexity,and low precision of device fabrication.Herein,we report the directed self-assembly of mononuclear anthraquinone(MAQ)derivatives and porous lignin-based graphene oxide(PLGO)into a renewable colloidal gel through noncovalent interactions.These self-assembled gel electrode materials exhibited high capacitance(484.8 F g^(−1) at a current density of 1 A g^(−1))and could be further printed as flexible micro-supercapacitors(FMSCs)with arbitrary patterns and a relatively high resolution on specific substrates.The FMSCs exhibited excellent areal capacitance(43.6 mF cm^(−2)),energy and power densities(6.1μWh cm^(−2) and 50μW cm^(−2),respectively),and cycle stability(>10,000 cycles).Furthermore,the printed FMSCs and integrated FMSC arrays exhibited remarkable flexibility while maintaining a stable capacitance.The proposed approach can be applied to other quinone biomolecules and biomass-based carbon materials.This study provides a basis for fabricating green and sustainable energy storage device architectures with high capacitance,long-term cycling,high scalability,and high precision.展开更多
The yields of X_(cscs)with its two possible configurations,i.e.,the hadronic molecular state and tetraquark state,for Pb-Pb collisions at√sNN=5.02 TeV is studied.A volume effect is found from the centrality distribut...The yields of X_(cscs)with its two possible configurations,i.e.,the hadronic molecular state and tetraquark state,for Pb-Pb collisions at√sNN=5.02 TeV is studied.A volume effect is found from the centrality distribution of X_(cscs),which could help to distinguish the inner structure of X_(cscs).We also show the rapidity and the transverse momentum distributions of X_(cscs) production as well as its elliptic flow coefficient as a function of the transverse momentum.展开更多
Conventional reactive sites of ketones with aldehydes lie on the carbonyl andα-carbon positions,which lead to a wide range of classic reactions such as pinacol-coupling and aldol-type condensations.Herein,an unpreced...Conventional reactive sites of ketones with aldehydes lie on the carbonyl andα-carbon positions,which lead to a wide range of classic reactions such as pinacol-coupling and aldol-type condensations.Herein,an unprecedented reactive site of aromatic ketones toward aldehydes has been revealed by using earth-abundant manganese catalysis,which enabled the first deoxygenative[3+2]annulations of ketones and aldehydes through C–H activation affording isobenzofuran derivatives.Mechanistic studies give hints on the dual role of triphenylborane additive in the reaction,that is,promoting C–H activation as a transmetalation reagent and activating aldehydes as a Lewis acid.展开更多
A manganese-catalyzed bicyclic annulation of imines with α,β-unsaturated esters via C–H activation is described, which provides an expedient access to fused β-lactams in one-step operation with high efficiency and...A manganese-catalyzed bicyclic annulation of imines with α,β-unsaturated esters via C–H activation is described, which provides an expedient access to fused β-lactams in one-step operation with high efficiency and good functional group tolerance. Of note, both ketimines and aldimines are amenable to this transformation. Mechanistic studies have identified a five-membered azamanganacycle as the key reaction intermediate.展开更多
The recently reported non-fullerene acceptor(NFA)Y6 has been extensively investigated for high-performance organic solar cells.However,its charge transport property and physics have not been fully studied.In this work...The recently reported non-fullerene acceptor(NFA)Y6 has been extensively investigated for high-performance organic solar cells.However,its charge transport property and physics have not been fully studied.In this work,we acquired a deeper understanding of the charge transport in Y6 by fabricating and characterizing thin-film transistors(TFTs),and found that the electron mobility of Y6 is over 0.3-0.4 cm^(2)/(V⋅s)in top-gate bottom-contact devices,which is at least one order of magnitude higher than that of another well-known NFA ITIC.More importantly,we observed band-like transport in Y6 spin-coated films through temperature-dependent measurements on TFTs.This is particularly amazing since such transport behavior is rarely seen in polycrystalline organic semiconductor films.Further morphology characterization and discussions indicate that the band-like transport originates from the unique molecule packing motif of Y6 and the special phase of the film.As such,this work not only demonstrates the superior charge transport property of Y6,but also suggests the great potential of developing high-mobility n-type organic semiconductors,on the basis of Y6.展开更多
The amphiphilic derivatives of L-histidine with different alkyl chains, NIPCA, UIPCA, and TIPCA, have been designed and their self-assembly behaviors with citric acid were investigated. All L-histidine derivatives can...The amphiphilic derivatives of L-histidine with different alkyl chains, NIPCA, UIPCA, and TIPCA, have been designed and their self-assembly behaviors with citric acid were investigated. All L-histidine derivatives can form hydrogels with citric acid, and exhibit the increasing gelation ability and mechanical strength with the increasing chain length. The gelation ability is considered to be affected by the synergistic effect of electrostatic interaction, hydrogen bonding and hydrophobic interaction. The hydrogels exhibit excellent releasing selectivity for charged dyes in aqueous solution, enlightening people to utilize this kind of hydrogels as intelligent carriers to separate the mixtures of charged dyes.展开更多
基金The National Key R&D Program of China under contract Nos 2020YFD0901202 and 2019YFD0901502the National Natural Science Foundation of China under contract Nos 41806110,41506151 and 31902426。
文摘In the western and central Pacific Ocean,upper strata waters exhibit highly dynamic oceanographic features under ENSO variability.This has been proved to be responsible for the dynamic change of both abundance and zonal distribution of skipjack tuna(Katsuwonus pelamis).Although causality has been suggested by researchers using physical-biological interaction models,cumulative evidence needs to be obtained and the tenability of assertion needs to be tested from an ecological habitat perspective,based on fisheries data.For purse seine fishery,the use of catch per unit effort(CPUE)as an indication of the abundance is confusing because of technical improvements over the whole exploitation history and unbalanced individual fishing characteristic of vessels.It is particularly interesting to discriminate between habitat characteristics in comparative scenarios of CPUE application.This study identified habitat traits based on a series of oceanographic factors from a global ocean reanalysis model.A comparison was conducted between two habitat models based on unprocessed purse seine CPUE and standardized CPUE considering fishing characteristics.The results suggest that standardized CPUE could model the regular zonal shift of habitat compatible with the observed fishing efforts transfer,and achieved better prediction capacity than unprocessed CPUE.Furthermore,the habitat of skipjack tuna was also characterized and linked with surface and subsurface thermal environment,ocean current,dissolved oxygen,biotic environment,and ENSO variability.The monthly-averaged habitat suitable index,derived from the optimal habitat model prediction,showed a significant linear relationship with the southern oscillation index,which suggested that El Ni?o episodes eventually provide more preferable habitat for skipjack tuna under ENSO variability.
文摘The robust stability of uncertain neutral systems with mixed time-varying delays is investigated in this paper. The uncertainties under consideration are norm-bounded and time-varying. Based on the Lyapunov stability theory, a delay-dependent stability criterion is derived and given in the form of a linear matrix inequality （LMI）. Finally, a numerical example is given to illustrate significant improvement over some existing results.
文摘Phase-transfer-catalyzed intramolecular cyclization reaction of forming benzo[b]furan and 3-methyleneisoin- doline-1-one derivatives has been developed. The cyclization reaction of propargylic carbonates was also de- scribed under metal-free condition and the reaction was reported by Pd and Ni before. The reaction condi- tions and the scope of the process are examined. The catalysts are cheap and environmentally friendly and the substrates are readily available and the procedure is simple, rapid, and general. The development of C-O and C-N bond formation processes via an overall structural isomerization represents the most atom-eco- nomical approach.
基金funded by the National Natural Science Foundation of China(61872203 and 61802212)the Shandong Provincial Natural Science Foundation(ZR2019BF017)+3 种基金Major Scientific and Technological Innovation Projects of Shandong Province(2019JZZY010127,2019JZZY010132,and 2019JZZY010201)Jinan City“20 universities”Funding Projects Introducing Innovation Team Program(2019GXRC031)Plan of Youth Innovation Team Development of colleges and universities in Shandong Province(SD2019-161)the Project of Shandong Province Higher Educational Science and Technology Program(J18KA331).
文摘This paper presents an algorithm to solve the problem of Photo-Response Non-Uniformity(PRNU)noise facing stabilized video.The stabilized video undergoes in-camera processing like rolling shutter correction.Thus,misalignment exists between the PRNU noises in the adjacent frames owing to the global and local frame registration performed by the in-camera processing.The misalignment makes the reference PRNU noise and the test PRNU noise unable to extract and match accurately.We design a computing method of maximum likelihood estimation algorithm for extracting the PRNU noise from stabilized video frames.Besides,unlike most prior arts tending to match the PRNU noise in whole frame,we propose a new patch-based matching strategy,aiming at reducing the influence from misalignment of frame the PRNU noise.After extracting the reference PRNU noise and the test PRNU noise,this paper adopts the reference and the test PRNU overlapping patch-based matching.It is different from the traditional matching method.This paper conducts different experiments on 224 stabilized videos taken by 13 smartphones in the VISION database.The area under curve of the algorithm proposed in this paper is 0.841,which is significantly higher than 0.805 of the whole frame matching in the traditional algorithm.Experimental results show good performance and effectiveness the proposed strategy by comparing with the prior arts.
基金supported by the National Natural Science Foundation of China(U21A20497,62374033)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZZ129)。
基金the National Natural Science Foundation of China (Nos.22375059, 22005133, 51922039 and52273174)Shenzhen Science and Technology Program (No.RCJC20200714114434015)+1 种基金Science and Technology Innovation Program of Hunan Province (No.2020RC5033)National Key Research and Development Program of China (No.2020YFC1807302) for financial support。
文摘While heteroatom doping serves as a powerful strategy for devising novel polycyclic aromatic hydrocarbons(PAHs), the further fine-tuning of optoelectronic properties via the precisely altering of doping patterns remains a challenge. Herein, by changing the doping positions of heteroatoms in a diindenopyrene skeleton, we report two isomeric boron, sulfur-embedded PAHs, named Anti-B_(2)S_(2) and Syn-B_(2)S_(2), as electron transporting semiconductors. Detailed structure-property relationship studies revealed that the varied heteroatom positions not only change their physicochemical properties, but also largely affect their solid-state packing modes and Lewis base-triggered photophysical responses. With their low-lying frontier molecular orbital levels, n-type characteristics with electron mobilities up to 1.5 × 10^(-3)cm^(2)V^(-1)s^(-1)were achieved in solution-processed organic field-effect transistors. Our work revealed the critical role of controlling heteroatom doping patterns for designing advanced PAHs.
基金supported by the National Natural Science Foundation of China(62175061,52172140,52221001,and 52072117)the Natural Science Foundation of Hunan Province(2022JJ30167)+1 种基金the Outstanding Scholarship Program of Hunan Province(2021JJ10021)China Postdoctoral Science Foundation(BX20220104,2022M720046 and 2022TQ0100)。
基金supported by the Ministry of Science and Technology of China(2018YFA0703200 and 2022YFB3603800)the National Natural Science Foundation of China(21875259,52233010,51725304,61890943 and 22021002)+4 种基金the Chinese Academy of Sciences Project for Young Scientists in Basic Research(YSBR-053)the Youth Innovation Promotion Association of the Chinese Academy of Sciencesthe National Program for Support of Top-notch Young ProfessionalsBeijing National Laboratory for Molecular Sciences(BNLMS-CXXM-202012)the Key Research Program of the Chinese Academy of Sciences(XDPB13)。
基金supported by the National Natural Science Foundation of China(Grant Nos.21905069 and U21A20307)the Shenzhen Science and Technology Innovation Committee(Grant Nos.ZDSYS20190902093220279,KQTD20170809110344233,GXWD20201230155427003-20200821181245001,GXWD20201230155427003-20200821181809001,and ZX20200151)+1 种基金the Department of Science and Technology of Guangdong Province(Grant No.2020A1515110879)University Stable Support Foundation of Shenzhen(Grant No.GXWD20201230155427003-20200821181809001).
文摘Biomass carbon and small redox biomolecules are attractive materials for green,sustainable energy storage devices owing to their environmentally friendly,low-cost,scalable,and novel sources.However,most devices manufactured using these materials have low specific capacitance,poor cycle stability,short lifetime,complexity,and low precision of device fabrication.Herein,we report the directed self-assembly of mononuclear anthraquinone(MAQ)derivatives and porous lignin-based graphene oxide(PLGO)into a renewable colloidal gel through noncovalent interactions.These self-assembled gel electrode materials exhibited high capacitance(484.8 F g^(−1) at a current density of 1 A g^(−1))and could be further printed as flexible micro-supercapacitors(FMSCs)with arbitrary patterns and a relatively high resolution on specific substrates.The FMSCs exhibited excellent areal capacitance(43.6 mF cm^(−2)),energy and power densities(6.1μWh cm^(−2) and 50μW cm^(−2),respectively),and cycle stability(>10,000 cycles).Furthermore,the printed FMSCs and integrated FMSC arrays exhibited remarkable flexibility while maintaining a stable capacitance.The proposed approach can be applied to other quinone biomolecules and biomass-based carbon materials.This study provides a basis for fabricating green and sustainable energy storage device architectures with high capacitance,long-term cycling,high scalability,and high precision.
基金Supported by Guangdong Major Project of Basic and Applied Basic Research(2020B0301030008)the National Natural Science Foundation of China(12105107)Science and Technology Program of Guangzhou(2019050001)。
文摘The yields of X_(cscs)with its two possible configurations,i.e.,the hadronic molecular state and tetraquark state,for Pb-Pb collisions at√sNN=5.02 TeV is studied.A volume effect is found from the centrality distribution of X_(cscs),which could help to distinguish the inner structure of X_(cscs).We also show the rapidity and the transverse momentum distributions of X_(cscs) production as well as its elliptic flow coefficient as a function of the transverse momentum.
基金support from the National Natural Science Foundation of China(21772202,21831008)Beijing Municipal Science&Technology Commission(project No.Z191100007219009)Beijing National Laboratory for Molecular Sciences(BNLMS-CXXM-201901)are gratefully acknowledged.
文摘Conventional reactive sites of ketones with aldehydes lie on the carbonyl andα-carbon positions,which lead to a wide range of classic reactions such as pinacol-coupling and aldol-type condensations.Herein,an unprecedented reactive site of aromatic ketones toward aldehydes has been revealed by using earth-abundant manganese catalysis,which enabled the first deoxygenative[3+2]annulations of ketones and aldehydes through C–H activation affording isobenzofuran derivatives.Mechanistic studies give hints on the dual role of triphenylborane additive in the reaction,that is,promoting C–H activation as a transmetalation reagent and activating aldehydes as a Lewis acid.
基金supported by the National Basic Research Program of China (2012CB821600)the National Natural Science Foundation of China (21322203, 21272238, 21521002)
文摘A manganese-catalyzed bicyclic annulation of imines with α,β-unsaturated esters via C–H activation is described, which provides an expedient access to fused β-lactams in one-step operation with high efficiency and good functional group tolerance. Of note, both ketimines and aldimines are amenable to this transformation. Mechanistic studies have identified a five-membered azamanganacycle as the key reaction intermediate.
基金The authors thank the National Key Research and Development Program(No.2021YFA1200700)the National Natural Science Foundation of China(Grant Nos.62074054 and U21A20497)+1 种基金the Natural Science Foundation of Hunan Province(Nos.2019GK2245 and 2020JJ1002)Shenzhen Science and Technology Innovation Commission(No.RCYX20200714114537036)for financial support.The work was also supported by the Fundamental Research Funds for the Central Universities.
文摘The recently reported non-fullerene acceptor(NFA)Y6 has been extensively investigated for high-performance organic solar cells.However,its charge transport property and physics have not been fully studied.In this work,we acquired a deeper understanding of the charge transport in Y6 by fabricating and characterizing thin-film transistors(TFTs),and found that the electron mobility of Y6 is over 0.3-0.4 cm^(2)/(V⋅s)in top-gate bottom-contact devices,which is at least one order of magnitude higher than that of another well-known NFA ITIC.More importantly,we observed band-like transport in Y6 spin-coated films through temperature-dependent measurements on TFTs.This is particularly amazing since such transport behavior is rarely seen in polycrystalline organic semiconductor films.Further morphology characterization and discussions indicate that the band-like transport originates from the unique molecule packing motif of Y6 and the special phase of the film.As such,this work not only demonstrates the superior charge transport property of Y6,but also suggests the great potential of developing high-mobility n-type organic semiconductors,on the basis of Y6.
基金funded by the National Natural Science Foundation of China(No. 21573134)
文摘The amphiphilic derivatives of L-histidine with different alkyl chains, NIPCA, UIPCA, and TIPCA, have been designed and their self-assembly behaviors with citric acid were investigated. All L-histidine derivatives can form hydrogels with citric acid, and exhibit the increasing gelation ability and mechanical strength with the increasing chain length. The gelation ability is considered to be affected by the synergistic effect of electrostatic interaction, hydrogen bonding and hydrophobic interaction. The hydrogels exhibit excellent releasing selectivity for charged dyes in aqueous solution, enlightening people to utilize this kind of hydrogels as intelligent carriers to separate the mixtures of charged dyes.
