Surface tension-induced shrinkage of heterogeneously bonded interfaces is a key factor in limiting the performance of nanostructures.Herein,we demonstrate a laser-induced thermo-compression bonding technology to suppr...Surface tension-induced shrinkage of heterogeneously bonded interfaces is a key factor in limiting the performance of nanostructures.Herein,we demonstrate a laser-induced thermo-compression bonding technology to suppress surface tension-induced shrinkage of Cu-Au bonded interface.A focused laser beam is used to apply localized heating and scattering force to the exposed Cu nanowire.The laser-induced scattering force and the heating can be adjusted by regulating the exposure intensity.When the ratio of scattering forces to the gravity of the exposed nanowire reaches 3.6×10^(3),the molten Cu nanowire is compressed into flattened shape rather than shrinking into nanosphere by the surface tension.As a result,the Cu-Au bonding interface is broadened fourfold by the scattering force,leading to a reduction in contact resistance of approximately 56%.This noncontact thermo-compression bonding technology provides significant possibilities for the interconnect packaging and integration of nanodevices.展开更多
Endogenously eliminating the hematoma is a favorable strategy in addressing intracerebral hemorrhage(ICH).This study sought to determine the role of retinoid X receptor-ot(RXR-a)in the context of hematoma absorption a...Endogenously eliminating the hematoma is a favorable strategy in addressing intracerebral hemorrhage(ICH).This study sought to determine the role of retinoid X receptor-ot(RXR-a)in the context of hematoma absorption after ICH.Our results showed that pharmacologically activating RXR-a with bexarotene significantly accelerated hematoma clearance and alleviated neurological dysfunction after ICH.RXR-ot was expressed in microglia/macro-phages,neurons,and astrocytes.Mechanistically,bexarotene promoted the nuclear translocation of RXR-a and PPAR-y,as well as reducing neuroinflammation by modulating microglia/macrophage reprograming from the Ml into the M2 phenotype.Furthermore,all the beneficial effects of RXR-a in ICH were reversed by the PPAR-y inhibitor GW9662.In conclusion,the pharmacological activation of RXR-a confers robust neuroprotection against ICH by accelerating hematoma clearance and repolarizing microglia/macrophages towards the M2 phenotype through PPAR-y-related mechanisms.Our data support the notion that RXR-ot might be a promising therapeutic target for ICH.展开更多
In multi-infeed HVDC system, the interactions and influences between DC systems AC systems are complex as the electrical distances among DC converter stations which are relatively short. Multi-infeed interaction facto...In multi-infeed HVDC system, the interactions and influences between DC systems AC systems are complex as the electrical distances among DC converter stations which are relatively short. Multi-infeed interaction factor (MIIF) can effectively reflect the interaction among DC systems. The paper theoretically analyzes the impact factors of MIIF like the electrical distances between two DC converter stations and the equivalent impedance of the receiving end AC system. By applying the Kirchhoff’s current law on the inverter AC bus, the paper deduces the analytical expressions for MIIF. From the expression, it is clear how the equivalent impedance of AC system and coupling impedance can affect MIIF. PSCAD simulations validate the effectiveness and the correctness of the proposed expression and some useful conclusions are drawn.展开更多
AlGaInP-based red miniaturized light-emitting diode(mini-LED)is a key component in realizing a full-color display.One of the main obstacles originates from interfacial recombination at the AlGaInP-SiO_(2)interface,and...AlGaInP-based red miniaturized light-emitting diode(mini-LED)is a key component in realizing a full-color display.One of the main obstacles originates from interfacial recombination at the AlGaInP-SiO_(2)interface,and it is crucial to develop effective surface passivation strategies to achieve higher external quantum efficiency(EQE)in AlGaInP-based red mini-LEDs.Here,we demonstrated AlGaInP-based red flip-chip mini-LEDs with an AlN passivation layer via atomic layer deposition(ALD).Utilizing a Monte Carlo ray tracing method,we investigated the effects of the SiO_(2)passivation layer and the Al N passivation layer on the optical performances of mini-LEDs.Since the refractive index of AlN is between AlGaInP and SiO_(2),the total internal reflection is alleviated and light extraction is enhanced.Unexpectedly,the AlN passivation layer also contributes to improving the current spreading ability of mini-LEDs,which is demonstrated by the near-field light distribution.Benefiting from superior light extraction and improved current spreading,the EQE of the mini-LED with an AlN passivation layer realizes an increment of 16.1%at 5 mA,in comparison to the mini-LED with a SiO_(2)passivation layer.The EQE of miniLEDs with an AlN passivation layer reaches a competitive value of 22.3%at 5 mA,surpassing previously reported AlGaInPbased red mini-LEDs.Moreover,the high temperature-humidity aging test exhibits that the AlN passivation layer effectively enhances the reliability of mini-LEDs.This work provides guidance for high-performance AlGaInP-based red flip-chip miniLEDs design and manufacture.展开更多
III-nitride materials are of great importance in the development of modern optoelectronics,but they have been limited over years by low light utilization rate and high dislocation densities in heteroepitaxial films gr...III-nitride materials are of great importance in the development of modern optoelectronics,but they have been limited over years by low light utilization rate and high dislocation densities in heteroepitaxial films grown on foreign substrate with limited refractive index contrast and large lattice mismatches.Here,we demonstrate a paradigm of high-throughput manufacturing bioinspired microstructures on warped substrates by flexible nanoimprint lithography for promoting the light extraction capability.We design a flexible nanoimprinting mold of copolymer and a two-step etching process that enable high-efficiency fabrication of nanoimprinted compound-eye-like Al2O3 microstructure(NCAM)and nanoimprinted compound-eye-like SiO_(2)microstructure(NCSM)template,achieving a 6.4-fold increase in throughput and 25%savings in economic costs over stepper projection lithography.Compared to NCAM template,we find that the NCSM template can not only improve the light extraction capability,but also modulate the morphology of AlN nucleation layer and reduce the formation of misoriented GaN grains on the inclined sidewall of microstructures,which suppresses the dislocations generated during coalescence,resulting in 40%reduction in dislocation density.This study provides a low-cost,high-quality,and high-throughput solution for manufacturing microstructures on warped surfaces of III-nitride optoelectronic devices.展开更多
Triticum urartu is the progenitor of the A subgenome in tetraploid and hexaploid wheat.Uncovering the landscape of genetic variations in T.urartu will help us understand the evolutionary and polyploid characteristics ...Triticum urartu is the progenitor of the A subgenome in tetraploid and hexaploid wheat.Uncovering the landscape of genetic variations in T.urartu will help us understand the evolutionary and polyploid characteristics of wheat.Here,we investigated the population genomics of T.urartu by genome-wide sequencing of 59 representative accessions collected around the world.A total of 42.2 million highquality single-nucleotide polymorphisms and 3 million insertions and deletions were obtained by mapping reads to the reference genome.The ancient T.urartu population experienced a significant reduction in effective population size(Ne)from3000000 to140000 and subsequently split into eastern Mediterranean coastal and Mesopotamian-Transcaucasian populations during the Younger Dryas period.A map of allelic drift paths displayed splits and mixtures between different geographic groups,and a strong genetic drift towards hexaploid wheat was also observed,indicating that the direct donor of the A subgenome originated from northwestern Syria.Genetic changes were revealed between the eastern Mediterranean coastal and Mesopotamian-Transcaucasian populations in genes orthologous to those regulating plant development and stress responses.A genome-wide association study identified two single-nucleotide polymorphisms in the exonic regions of the SEMI-DWARF 37 ortholog that corresponded to the different T.urartu ecotype groups.Our study provides novel insights into the origin and genetic legacy of the A subgenome in polyploid wheat and contributes a gene repertoire for genomicsenabled improvements in wheat breeding.展开更多
Solar-blind ultraviolet photodetectors(SBPDs)have attracted tremendous attention in the environmental,industrial,military,and biological fields.Aluminum gallium nitride(AlGaN),a kind of representative III-nitride semi...Solar-blind ultraviolet photodetectors(SBPDs)have attracted tremendous attention in the environmental,industrial,military,and biological fields.Aluminum gallium nitride(AlGaN),a kind of representative III-nitride semiconductor,has promising prospects in solar-blind photodetection owing to its tunable wide bandgap and industrial feasibility.Considering the high defect density in the AlGaN epilayer directly grown on a sapphire substrate,employing an AlN/sapphire template turns out to be an effective method to achieve a high-quality AlGaN epilayer,thereby enhancing the SBPD performances.In recent years,a variety of remarkable breakthroughs have been achieved in the SBPDs.In this paper,the progress on photovoltaic AlGaN-based SBPDs is reviewed.First,the basic physical properties of AlGaN are introduced.Then,fabrication methods and defect annihilation of the AlN/sapphire template are discussed.Various photovoltaic SBPDs are further summarized,including Schottky barrier,metal-semiconductor-metal,p-n/p-i-n and avalanche photodiodes.Furthermore,surface modification and photoelectrochemical cell techniques are introduced.Benefitting from the development of fabrication techniques and optoelectronic devices,photovoltaic AlGaN photodiodes exhibit a promising prospect in solar-blind ultraviolet photodetection.展开更多
AlGaN-based light-emitting diodes(LEDs)operating in the deep-ultraviolet(DUV)spectral range(210–280 nm)have demonstrated potential applications in physical sterilization.However,the poor external quantum efficiency(E...AlGaN-based light-emitting diodes(LEDs)operating in the deep-ultraviolet(DUV)spectral range(210–280 nm)have demonstrated potential applications in physical sterilization.However,the poor external quantum efficiency(EQE)hinders further advances in the emission performance of AlGaN-based DUV LEDs.Here,we demonstrate the performance of 270-nm AlGaN-based DUV LEDs beyond the state-of-the-art by exploiting the innovative combination of bandgap engineering and device craft.By adopting tailored multiple quantum wells(MQWs),a reflective Al reflector,a low-optical-loss tunneling junction(TJ)and a dielectric SiO_(2)insertion structure(IS-SiO_(2)),outstanding light output powers(LOPs)of 140.1 mW are achieved in our DUV LEDs at 850 mA.The EQEs of our DUV LEDs are 4.5 times greater than those of their conventional counterparts.This comprehensive approach overcomes the major difficulties commonly faced in the pursuit of high-performance AlGaN-based DUV LEDs,such as strong quantum-confined Stark effect(QCSE),severe optical absorption in the p-electrode/ohmic contact layer and poor transverse magnetic(TM)-polarized light extraction.Furthermore,the on-wafer electroluminescence characterization validated the scalability of our DUV LEDs to larger production scales.Our work is promising for the development of highly efficient AlGaN-based DUV LEDs.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52305612 and U20A6004)Open Fund of Hubei Key Laboratory of Electronic Manufacturing and Packaging Integration(Wuhan University)(NO.EMPI2023015).
文摘Surface tension-induced shrinkage of heterogeneously bonded interfaces is a key factor in limiting the performance of nanostructures.Herein,we demonstrate a laser-induced thermo-compression bonding technology to suppress surface tension-induced shrinkage of Cu-Au bonded interface.A focused laser beam is used to apply localized heating and scattering force to the exposed Cu nanowire.The laser-induced scattering force and the heating can be adjusted by regulating the exposure intensity.When the ratio of scattering forces to the gravity of the exposed nanowire reaches 3.6×10^(3),the molten Cu nanowire is compressed into flattened shape rather than shrinking into nanosphere by the surface tension.As a result,the Cu-Au bonding interface is broadened fourfold by the scattering force,leading to a reduction in contact resistance of approximately 56%.This noncontact thermo-compression bonding technology provides significant possibilities for the interconnect packaging and integration of nanodevices.
基金by the National Key R&D Program of China(2018YFC1312600 and 2018YFC1312603)the Key Research and Development Project of Zhejiang Province(2018C03011)+1 种基金the National Natural Science Foundation of China(81771246,81971099,and 81870908)the Scientific Research Fund of Zhejiang Provincial Education Department(Y201941838).
文摘Endogenously eliminating the hematoma is a favorable strategy in addressing intracerebral hemorrhage(ICH).This study sought to determine the role of retinoid X receptor-ot(RXR-a)in the context of hematoma absorption after ICH.Our results showed that pharmacologically activating RXR-a with bexarotene significantly accelerated hematoma clearance and alleviated neurological dysfunction after ICH.RXR-ot was expressed in microglia/macro-phages,neurons,and astrocytes.Mechanistically,bexarotene promoted the nuclear translocation of RXR-a and PPAR-y,as well as reducing neuroinflammation by modulating microglia/macrophage reprograming from the Ml into the M2 phenotype.Furthermore,all the beneficial effects of RXR-a in ICH were reversed by the PPAR-y inhibitor GW9662.In conclusion,the pharmacological activation of RXR-a confers robust neuroprotection against ICH by accelerating hematoma clearance and repolarizing microglia/macrophages towards the M2 phenotype through PPAR-y-related mechanisms.Our data support the notion that RXR-ot might be a promising therapeutic target for ICH.
文摘In multi-infeed HVDC system, the interactions and influences between DC systems AC systems are complex as the electrical distances among DC converter stations which are relatively short. Multi-infeed interaction factor (MIIF) can effectively reflect the interaction among DC systems. The paper theoretically analyzes the impact factors of MIIF like the electrical distances between two DC converter stations and the equivalent impedance of the receiving end AC system. By applying the Kirchhoff’s current law on the inverter AC bus, the paper deduces the analytical expressions for MIIF. From the expression, it is clear how the equivalent impedance of AC system and coupling impedance can affect MIIF. PSCAD simulations validate the effectiveness and the correctness of the proposed expression and some useful conclusions are drawn.
基金supported by the Wuhan Joint Innovation Laboratory of Advanced Display Industry(Grant No.2024010902040449)the National Natural Science Foundation of China(Grant Nos.52075394,52475601)+4 种基金the National Key Research and Development Program of China(Grant Nos.2022YFB3603603,2021YFB3600204)the National Youth Talent Support Program,the Key Research and Development Program of Hubei Province(Grant No.2023BAB137)the Knowledge Innovation Program of Wuhan-Basic Research(Grant No.2023010201010068)the Science and Technology Major Project of Hubei Province(Grant No.2024BAA004)the Science and Technology Major Project of Wuhan(Grant No.2024010702020024)。
文摘AlGaInP-based red miniaturized light-emitting diode(mini-LED)is a key component in realizing a full-color display.One of the main obstacles originates from interfacial recombination at the AlGaInP-SiO_(2)interface,and it is crucial to develop effective surface passivation strategies to achieve higher external quantum efficiency(EQE)in AlGaInP-based red mini-LEDs.Here,we demonstrated AlGaInP-based red flip-chip mini-LEDs with an AlN passivation layer via atomic layer deposition(ALD).Utilizing a Monte Carlo ray tracing method,we investigated the effects of the SiO_(2)passivation layer and the Al N passivation layer on the optical performances of mini-LEDs.Since the refractive index of AlN is between AlGaInP and SiO_(2),the total internal reflection is alleviated and light extraction is enhanced.Unexpectedly,the AlN passivation layer also contributes to improving the current spreading ability of mini-LEDs,which is demonstrated by the near-field light distribution.Benefiting from superior light extraction and improved current spreading,the EQE of the mini-LED with an AlN passivation layer realizes an increment of 16.1%at 5 mA,in comparison to the mini-LED with a SiO_(2)passivation layer.The EQE of miniLEDs with an AlN passivation layer reaches a competitive value of 22.3%at 5 mA,surpassing previously reported AlGaInPbased red mini-LEDs.Moreover,the high temperature-humidity aging test exhibits that the AlN passivation layer effectively enhances the reliability of mini-LEDs.This work provides guidance for high-performance AlGaInP-based red flip-chip miniLEDs design and manufacture.
基金supported by the National Natural Science Foundation of China(52075394)the National Key R&D Program of China(2022YFB3603603 and 2021YFB3600204)+1 种基金the Key Research and Development Program of Hubei Province(2023BAB137)the Knowledge Innovation Program of Wuhan-Basic Research,the National Youth Talent Support Program,and the Fundamental Research Funds for the Central Universities.
文摘III-nitride materials are of great importance in the development of modern optoelectronics,but they have been limited over years by low light utilization rate and high dislocation densities in heteroepitaxial films grown on foreign substrate with limited refractive index contrast and large lattice mismatches.Here,we demonstrate a paradigm of high-throughput manufacturing bioinspired microstructures on warped substrates by flexible nanoimprint lithography for promoting the light extraction capability.We design a flexible nanoimprinting mold of copolymer and a two-step etching process that enable high-efficiency fabrication of nanoimprinted compound-eye-like Al2O3 microstructure(NCAM)and nanoimprinted compound-eye-like SiO_(2)microstructure(NCSM)template,achieving a 6.4-fold increase in throughput and 25%savings in economic costs over stepper projection lithography.Compared to NCAM template,we find that the NCSM template can not only improve the light extraction capability,but also modulate the morphology of AlN nucleation layer and reduce the formation of misoriented GaN grains on the inclined sidewall of microstructures,which suppresses the dislocations generated during coalescence,resulting in 40%reduction in dislocation density.This study provides a low-cost,high-quality,and high-throughput solution for manufacturing microstructures on warped surfaces of III-nitride optoelectronic devices.
基金This research was financially supported by the National Natural Science Foundation of China(31871617)the Ministry of Science and Technology of the People’s Republic of China(2016YFD0102002 and 2011AA100104).
文摘Triticum urartu is the progenitor of the A subgenome in tetraploid and hexaploid wheat.Uncovering the landscape of genetic variations in T.urartu will help us understand the evolutionary and polyploid characteristics of wheat.Here,we investigated the population genomics of T.urartu by genome-wide sequencing of 59 representative accessions collected around the world.A total of 42.2 million highquality single-nucleotide polymorphisms and 3 million insertions and deletions were obtained by mapping reads to the reference genome.The ancient T.urartu population experienced a significant reduction in effective population size(Ne)from3000000 to140000 and subsequently split into eastern Mediterranean coastal and Mesopotamian-Transcaucasian populations during the Younger Dryas period.A map of allelic drift paths displayed splits and mixtures between different geographic groups,and a strong genetic drift towards hexaploid wheat was also observed,indicating that the direct donor of the A subgenome originated from northwestern Syria.Genetic changes were revealed between the eastern Mediterranean coastal and Mesopotamian-Transcaucasian populations in genes orthologous to those regulating plant development and stress responses.A genome-wide association study identified two single-nucleotide polymorphisms in the exonic regions of the SEMI-DWARF 37 ortholog that corresponded to the different T.urartu ecotype groups.Our study provides novel insights into the origin and genetic legacy of the A subgenome in polyploid wheat and contributes a gene repertoire for genomicsenabled improvements in wheat breeding.
基金supported by the National Natural Science Foundation of China(Nos.52075394 and 51675386)the National Key Research and Development Program of China(No.2021YFB3600200)the National Youth Talent Support Program.
文摘Solar-blind ultraviolet photodetectors(SBPDs)have attracted tremendous attention in the environmental,industrial,military,and biological fields.Aluminum gallium nitride(AlGaN),a kind of representative III-nitride semiconductor,has promising prospects in solar-blind photodetection owing to its tunable wide bandgap and industrial feasibility.Considering the high defect density in the AlGaN epilayer directly grown on a sapphire substrate,employing an AlN/sapphire template turns out to be an effective method to achieve a high-quality AlGaN epilayer,thereby enhancing the SBPD performances.In recent years,a variety of remarkable breakthroughs have been achieved in the SBPDs.In this paper,the progress on photovoltaic AlGaN-based SBPDs is reviewed.First,the basic physical properties of AlGaN are introduced.Then,fabrication methods and defect annihilation of the AlN/sapphire template are discussed.Various photovoltaic SBPDs are further summarized,including Schottky barrier,metal-semiconductor-metal,p-n/p-i-n and avalanche photodiodes.Furthermore,surface modification and photoelectrochemical cell techniques are introduced.Benefitting from the development of fabrication techniques and optoelectronic devices,photovoltaic AlGaN photodiodes exhibit a promising prospect in solar-blind ultraviolet photodetection.
基金financial support from the National Natural Science Foundation of China(Nos.52075394 and 51675386)the National Key Research and Development Program of China(Nos.2021YFB3600200 and 2022YFB3603603)+1 种基金the Key Research and Development Program of Hubei Province(No.2023BAB137)the Knowledge Innovation Program of Wuhan-Basic Research,the Fundamental Research Funds for the Central Universities,and the National Youth Talent Support Program.
文摘AlGaN-based light-emitting diodes(LEDs)operating in the deep-ultraviolet(DUV)spectral range(210–280 nm)have demonstrated potential applications in physical sterilization.However,the poor external quantum efficiency(EQE)hinders further advances in the emission performance of AlGaN-based DUV LEDs.Here,we demonstrate the performance of 270-nm AlGaN-based DUV LEDs beyond the state-of-the-art by exploiting the innovative combination of bandgap engineering and device craft.By adopting tailored multiple quantum wells(MQWs),a reflective Al reflector,a low-optical-loss tunneling junction(TJ)and a dielectric SiO_(2)insertion structure(IS-SiO_(2)),outstanding light output powers(LOPs)of 140.1 mW are achieved in our DUV LEDs at 850 mA.The EQEs of our DUV LEDs are 4.5 times greater than those of their conventional counterparts.This comprehensive approach overcomes the major difficulties commonly faced in the pursuit of high-performance AlGaN-based DUV LEDs,such as strong quantum-confined Stark effect(QCSE),severe optical absorption in the p-electrode/ohmic contact layer and poor transverse magnetic(TM)-polarized light extraction.Furthermore,the on-wafer electroluminescence characterization validated the scalability of our DUV LEDs to larger production scales.Our work is promising for the development of highly efficient AlGaN-based DUV LEDs.
