Abundant efforts have been devoted to improving the efficiency of organic light-emitting diodes(OLEDs),however,approaches to control the device efficiency roll-off are still extremely limited,especially in nondoped bl...Abundant efforts have been devoted to improving the efficiency of organic light-emitting diodes(OLEDs),however,approaches to control the device efficiency roll-off are still extremely limited,especially in nondoped blue OLEDs.In this work,three blue emitters(TAT,TAMT and TAMT-CN)with"hot exciton"properties are designed and synthesized based on[1,2,4]triazolo[1,5-a]pyridine(TP)as a regulating unit as well as anthracene-triphenylamine(An-TPA)as the chromophore.By adjusting the linkage mode and modifying the TP unit,the excited state properties,carrier transfer abilities,horizontal orientation,and device efficiency roll-off were precisely controlled.Among these materials,emitters that directly connect the fused TP unit exhibit balanced charge-transporting ability,higher photoluminescent quantum yield and improved horizontal orientation,resulting in better electroluminescence(EL)performance in non-doped blue OLEDs.As a result,non-doped blue OLEDs exhibit excellent performance with external quantum efficiencies of over 6%,brightness of over 30,000 cd/m2and EL peaks of around 476 nm.More importantly,the device based on TAMT-CN exhibits an ultra-low efficiency roll-off of 2.97%at a high brightness of10,000 cd/m2.The accessible molecular unit and feasible design strategy in this work are of great significance for designing highly efficient and ultra-low efficiency roll-off non-doped blue OLEDs.展开更多
We study the connection between the central limit theorem and law of large numbers for exchangeable sequences, and provide a counterexample to the Gnedenko-Raikov theorem for such sequences.
Accumulating evidence has demonstrated that apoptotic vesicles(apoVs)derived from mesenchymal stem cells(MSCs;MSC-apoVs)are vital for bone regeneration,and possess superior capabilities compared to MSCs and other extr...Accumulating evidence has demonstrated that apoptotic vesicles(apoVs)derived from mesenchymal stem cells(MSCs;MSC-apoVs)are vital for bone regeneration,and possess superior capabilities compared to MSCs and other extracellular vesicles derived from MSCs(such as exosomes).The osteoinductive effect of MSC-apoVs is attributed to their diverse contents,especially enriched proteins or microRNAs(miRNAs).To optimize their osteoinduction activity,it is necessary to determine the unique cargo profiles of MSC-apoVs.We previously established the protein landscape and identified proteins specific to MSC-apoVs.However,the features and functions of miRNAs enriched in MSC-apoVs are unclear.In this study,we compared MSCs,MSC-apoVs,and MSC-exosomes from two types of MSC.We generated a map of miRNAs specific to MSC-apoVs and identified seven miRNAs specifically enriched in MSC-apoVs compared to MSCs and MSC-exosomes,which we classified as apoV-specific miRNAs.Among these seven specific miRNAs,hsa-miR-4485-3p was the most abundant and stable.Next,we explored its function in apoV-mediated osteoinduction.Unexpectedly,hsa-miR-4485-3p enriched in MSC-apoVs inhibited osteogenesis and promoted adipogenesis by targeting the AKT pathway.Tailored apoVs with downregulated hsa-miR-4485-3p exhibited a greater effect on bone regeneration than control apoVs.Like releasing the brake,we acquired more powerful osteoinductive apoVs.In summary,we identified the miRNA cargos,including miRNAs specific to MSC-apoVs,and generated tailored apoVs with high osteoinduction activity,which is promising in apoV-based therapies for bone regeneration.展开更多
Let{X,X_(n);n≥1}be a sequence of i.i.d.non-degenerate real-valued random variables with EX^(2)<∞.Let S_(n)=∑_(i=1)^(n)X_(i),n≥1.Let g(·):[0,∞)→[0,∞)be a nondecreasing regularly varying function with in...Let{X,X_(n);n≥1}be a sequence of i.i.d.non-degenerate real-valued random variables with EX^(2)<∞.Let S_(n)=∑_(i=1)^(n)X_(i),n≥1.Let g(·):[0,∞)→[0,∞)be a nondecreasing regularly varying function with indexρ≥0 and limt→∞g(t)=∞.Letμ=EX andσ^(2)=E(X−μ)^(2).In this paper,on the scale g(log n),we obtain precise asymptotic estimates for the probabilities of moderate deviations of the form log P(S_(n)−nμ>x√ng(log n)),log P(S_(n)−nμ<−x√ng(log n)),and log P(|S_(n)−nμ|>x√ng(log n))for all x>0.Unlike those known results in the literature,the moderate deviation results established in this paper depend on both the variance and the asymptotic behavior of the tail distribution of X.展开更多
The inception and harnessing of excitons are paramount for the electroluminescence performance of organic light-emitting devices(OLEDs).Through-space charge transfer(TSCT)via intramolecular interaction has proved to b...The inception and harnessing of excitons are paramount for the electroluminescence performance of organic light-emitting devices(OLEDs).Through-space charge transfer(TSCT)via intramolecular interaction has proved to be one of the most potent techniques employed to achieve 100% internal quantum efficiency.However,molecular strategies utilized to comprehensively enhance the electroluminescent performance of TSCT emitters regarding improving the photoluminescence quantum yield(PLQY)and elevating the light out-coupling efficiency remain arduous.To surmount this challenge,we deliberately designed and synthesized a proof-of-concept TSCT emitter called CzO-TRZ by incorporating an extra carbazole donor into spiroheterocyclic architecture.The introduction of rigid spiral fragments can immensely boost the horizontal orientation dipole ratio and establish an extra through-bond charge transfer(TBCT)radiative decay channel.As a result,a very high PLQY of 98.7%,fast kRISCof 2.2×10^(5)s^(-1)and high k_(r)^(s) of 2.2×10^(7)s^(-1),and an ultrahigh horizontal dipolar ratio of 90%were concurrently achieved for Cz O-TRZ blended films.Furthermore,corresponding thermally activated delayed fluorescence(TADF)-and TADF-sensitized fluorescence(TSF)-OLEDs based on CzO-TRZ demonstrated external quantum efficiencies(EQEs)of 33.4% and 30.3%,respectively,highlighting its versatile applications as both an emitter and sensitized host.展开更多
Mimicking and extending biological sensory memory processing functions and systems—that play significant roles in enhancing interconnections of the human-physical world—are highly preferable for the Internet of Thin...Mimicking and extending biological sensory memory processing functions and systems—that play significant roles in enhancing interconnections of the human-physical world—are highly preferable for the Internet of Things.However,conventional artificial sensory systems usually consisted of separated modules or relied on perception-memory-processing devices with applications in a limited domain.Here,we propose a self-rectifying multifunctional synapse based on a unique PN optoelectrical memristor interface,achieving an augmented artificial visual system and multifunctional interconnected ports.The synapse realizes in-sensor motion perception and non-contact control beyond perception-memory-processing functions.The self-rectifying device can self-suppress the sneak current in cross-arrays,enabling large-scale and high-density integration.Further integrating synapse with quantum dot light-emitting diodes(QLEDs)evolves more powerful functions like hardware noise filtering and perception-memory-processing-displaying smart systems.展开更多
P2-type layered Na_(0.67)MnO_(2)has been considered to be a promising candidate cathode material for sodium ion batteries.Nevertheless,the undesired phase transitions during operation and the large Na^(+)radius induce...P2-type layered Na_(0.67)MnO_(2)has been considered to be a promising candidate cathode material for sodium ion batteries.Nevertheless,the undesired phase transitions during operation and the large Na^(+)radius induced sluggish ion diffusion remain the stumbling blocks to realize its high performance.Herein,we propose a Zn/Mg co-doping strategy,which is proved to have bifunctional effects.First,relative to the pristine P2-Na_(0.67)MnO_(2)and the single-ion(Zn/Mg)doped samples,the Zn/Mg dual-doped P2-Na_(0.67)MnO_(2)demonstrates a lower Mn^(3+)/Mn^(4+)ratio and a higher lattice O content,which facilitate the structural stability of the cathode material.More intriguingly,the Zn/Mg co-doping gives rise to enlarged interplanar spacing,which provides spacious ion diffusion channels for fast Na^(+)intercalation/extraction.As a result,the Zn/Mg dual-doped sample exhibits a high Na^(+)diffusion coefficient and a solid-solution reaction during charge/discharge,with a cell volume change determined to be only 0.55%.Taking advantages of the above favorable features,the Zn/Mg dual-doped P2-Na_(0.67)MnO_(2)demonstrates a high rate performance with 67.2 mAh·g^(-1)delivered at 10 C and a decent cycling stability with a capacity retention of 93.8%achieved at 1 C after 100 cycles.This work introduces the Zn/Mg co-doping strategy to simultaneously improve the cycling stability and rate capability of P2-Na_(0.67)MnO_(2),which may offer a promising avenue for further performance enhancement of the layered Na-ion batteries cathode materials.展开更多
This paper deals with the conditional quantile estimation based on left-truncated and right-censored data.Assuming that the observations with multivariate covariates form a stationary α-mixing sequence,the authors de...This paper deals with the conditional quantile estimation based on left-truncated and right-censored data.Assuming that the observations with multivariate covariates form a stationary α-mixing sequence,the authors derive the strong convergence with rate,strong representation as well as asymptotic normality of the conditional quantile estimator.Also,a Berry-Esseen-type bound for the estimator is established.In addition,the finite sample behavior of the estimator is investigated via simulations.展开更多
基金the financial support from the National Natural Science Foundation of China(Nos.52273187 and 51973107)the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme 2019(No.GDUPS2019)。
文摘Abundant efforts have been devoted to improving the efficiency of organic light-emitting diodes(OLEDs),however,approaches to control the device efficiency roll-off are still extremely limited,especially in nondoped blue OLEDs.In this work,three blue emitters(TAT,TAMT and TAMT-CN)with"hot exciton"properties are designed and synthesized based on[1,2,4]triazolo[1,5-a]pyridine(TP)as a regulating unit as well as anthracene-triphenylamine(An-TPA)as the chromophore.By adjusting the linkage mode and modifying the TP unit,the excited state properties,carrier transfer abilities,horizontal orientation,and device efficiency roll-off were precisely controlled.Among these materials,emitters that directly connect the fused TP unit exhibit balanced charge-transporting ability,higher photoluminescent quantum yield and improved horizontal orientation,resulting in better electroluminescence(EL)performance in non-doped blue OLEDs.As a result,non-doped blue OLEDs exhibit excellent performance with external quantum efficiencies of over 6%,brightness of over 30,000 cd/m2and EL peaks of around 476 nm.More importantly,the device based on TAMT-CN exhibits an ultra-low efficiency roll-off of 2.97%at a high brightness of10,000 cd/m2.The accessible molecular unit and feasible design strategy in this work are of great significance for designing highly efficient and ultra-low efficiency roll-off non-doped blue OLEDs.
文摘We study the connection between the central limit theorem and law of large numbers for exchangeable sequences, and provide a counterexample to the Gnedenko-Raikov theorem for such sequences.
基金supported by grants from the National Natural Science Foundation of China(No.82170929 and 81970908 to Y.L.)the Beijing Natural Science Foundation(No.7222224 to X.Z.)。
文摘Accumulating evidence has demonstrated that apoptotic vesicles(apoVs)derived from mesenchymal stem cells(MSCs;MSC-apoVs)are vital for bone regeneration,and possess superior capabilities compared to MSCs and other extracellular vesicles derived from MSCs(such as exosomes).The osteoinductive effect of MSC-apoVs is attributed to their diverse contents,especially enriched proteins or microRNAs(miRNAs).To optimize their osteoinduction activity,it is necessary to determine the unique cargo profiles of MSC-apoVs.We previously established the protein landscape and identified proteins specific to MSC-apoVs.However,the features and functions of miRNAs enriched in MSC-apoVs are unclear.In this study,we compared MSCs,MSC-apoVs,and MSC-exosomes from two types of MSC.We generated a map of miRNAs specific to MSC-apoVs and identified seven miRNAs specifically enriched in MSC-apoVs compared to MSCs and MSC-exosomes,which we classified as apoV-specific miRNAs.Among these seven specific miRNAs,hsa-miR-4485-3p was the most abundant and stable.Next,we explored its function in apoV-mediated osteoinduction.Unexpectedly,hsa-miR-4485-3p enriched in MSC-apoVs inhibited osteogenesis and promoted adipogenesis by targeting the AKT pathway.Tailored apoVs with downregulated hsa-miR-4485-3p exhibited a greater effect on bone regeneration than control apoVs.Like releasing the brake,we acquired more powerful osteoinductive apoVs.In summary,we identified the miRNA cargos,including miRNAs specific to MSC-apoVs,and generated tailored apoVs with high osteoinduction activity,which is promising in apoV-based therapies for bone regeneration.
基金Supported by Natural Sciences and Engineering Research Council of Canada(Grant No.RGPIN-2019-06065)National Natural Science Foundation of China(Grant No.NSFC-11971154)。
文摘Let{X,X_(n);n≥1}be a sequence of i.i.d.non-degenerate real-valued random variables with EX^(2)<∞.Let S_(n)=∑_(i=1)^(n)X_(i),n≥1.Let g(·):[0,∞)→[0,∞)be a nondecreasing regularly varying function with indexρ≥0 and limt→∞g(t)=∞.Letμ=EX andσ^(2)=E(X−μ)^(2).In this paper,on the scale g(log n),we obtain precise asymptotic estimates for the probabilities of moderate deviations of the form log P(S_(n)−nμ>x√ng(log n)),log P(S_(n)−nμ<−x√ng(log n)),and log P(|S_(n)−nμ|>x√ng(log n))for all x>0.Unlike those known results in the literature,the moderate deviation results established in this paper depend on both the variance and the asymptotic behavior of the tail distribution of X.
基金supported by the National Natural Science Foundation of China(U21A20331,51773212,81903743,52003088)the Distinguished Young Scholars(21925506)the Ningbo Key Scientific and Technological Project(2022Z124,2022Z119)。
文摘The inception and harnessing of excitons are paramount for the electroluminescence performance of organic light-emitting devices(OLEDs).Through-space charge transfer(TSCT)via intramolecular interaction has proved to be one of the most potent techniques employed to achieve 100% internal quantum efficiency.However,molecular strategies utilized to comprehensively enhance the electroluminescent performance of TSCT emitters regarding improving the photoluminescence quantum yield(PLQY)and elevating the light out-coupling efficiency remain arduous.To surmount this challenge,we deliberately designed and synthesized a proof-of-concept TSCT emitter called CzO-TRZ by incorporating an extra carbazole donor into spiroheterocyclic architecture.The introduction of rigid spiral fragments can immensely boost the horizontal orientation dipole ratio and establish an extra through-bond charge transfer(TBCT)radiative decay channel.As a result,a very high PLQY of 98.7%,fast kRISCof 2.2×10^(5)s^(-1)and high k_(r)^(s) of 2.2×10^(7)s^(-1),and an ultrahigh horizontal dipolar ratio of 90%were concurrently achieved for Cz O-TRZ blended films.Furthermore,corresponding thermally activated delayed fluorescence(TADF)-and TADF-sensitized fluorescence(TSF)-OLEDs based on CzO-TRZ demonstrated external quantum efficiencies(EQEs)of 33.4% and 30.3%,respectively,highlighting its versatile applications as both an emitter and sensitized host.
基金supported by the National Natural Science Foundation of China(Grant No.62205063,62075043,62305254)Fujian Province Natural Science Foundation of China(Grant No.2023J05125,2022J05042)Fujian Normal University“Young Talent”Start-up Grant(Grant No.Y0720311K13)。
文摘Mimicking and extending biological sensory memory processing functions and systems—that play significant roles in enhancing interconnections of the human-physical world—are highly preferable for the Internet of Things.However,conventional artificial sensory systems usually consisted of separated modules or relied on perception-memory-processing devices with applications in a limited domain.Here,we propose a self-rectifying multifunctional synapse based on a unique PN optoelectrical memristor interface,achieving an augmented artificial visual system and multifunctional interconnected ports.The synapse realizes in-sensor motion perception and non-contact control beyond perception-memory-processing functions.The self-rectifying device can self-suppress the sneak current in cross-arrays,enabling large-scale and high-density integration.Further integrating synapse with quantum dot light-emitting diodes(QLEDs)evolves more powerful functions like hardware noise filtering and perception-memory-processing-displaying smart systems.
基金The authors are grateful to the financial supports from the National Natural Science Foundation of China(NSFC)(Nos.91834301,91534102,and 21808046)Anhui Provincial Science and Technology Department Foundation(No.201903a05020021).
文摘P2-type layered Na_(0.67)MnO_(2)has been considered to be a promising candidate cathode material for sodium ion batteries.Nevertheless,the undesired phase transitions during operation and the large Na^(+)radius induced sluggish ion diffusion remain the stumbling blocks to realize its high performance.Herein,we propose a Zn/Mg co-doping strategy,which is proved to have bifunctional effects.First,relative to the pristine P2-Na_(0.67)MnO_(2)and the single-ion(Zn/Mg)doped samples,the Zn/Mg dual-doped P2-Na_(0.67)MnO_(2)demonstrates a lower Mn^(3+)/Mn^(4+)ratio and a higher lattice O content,which facilitate the structural stability of the cathode material.More intriguingly,the Zn/Mg co-doping gives rise to enlarged interplanar spacing,which provides spacious ion diffusion channels for fast Na^(+)intercalation/extraction.As a result,the Zn/Mg dual-doped sample exhibits a high Na^(+)diffusion coefficient and a solid-solution reaction during charge/discharge,with a cell volume change determined to be only 0.55%.Taking advantages of the above favorable features,the Zn/Mg dual-doped P2-Na_(0.67)MnO_(2)demonstrates a high rate performance with 67.2 mAh·g^(-1)delivered at 10 C and a decent cycling stability with a capacity retention of 93.8%achieved at 1 C after 100 cycles.This work introduces the Zn/Mg co-doping strategy to simultaneously improve the cycling stability and rate capability of P2-Na_(0.67)MnO_(2),which may offer a promising avenue for further performance enhancement of the layered Na-ion batteries cathode materials.
基金supported by the National Natural Science Foundation of China(No.11271286)the Specialized Research Fund for the Doctor Program of Higher Education of China(No.20120072110007)a grant from the Natural Sciences and Engineering Research Council of Canada
文摘This paper deals with the conditional quantile estimation based on left-truncated and right-censored data.Assuming that the observations with multivariate covariates form a stationary α-mixing sequence,the authors derive the strong convergence with rate,strong representation as well as asymptotic normality of the conditional quantile estimator.Also,a Berry-Esseen-type bound for the estimator is established.In addition,the finite sample behavior of the estimator is investigated via simulations.
