In view of the complexity of existing linear frequency modulation(LFM)signal parameter estimation methods and the poor antinoise performance and estimation accuracy under a low signal-to-noise ratio(SNR),a parameter e...In view of the complexity of existing linear frequency modulation(LFM)signal parameter estimation methods and the poor antinoise performance and estimation accuracy under a low signal-to-noise ratio(SNR),a parameter estimation method for LFM signals with a Duffing oscillator based on frequency periodicity is proposed in this paper.This method utilizes the characteristic that the output signal of the Duffing oscillator excited by the LFM signal changes periodically with frequency,and the modulation period of the LFM signal is estimated by autocorrelation processing of the output signal of the Duffing oscillator.On this basis,the corresponding relationship between the reference frequency of the frequencyaligned Duffing oscillator and the frequency range of the LFM signal is analyzed by the periodic power spectrum method,and the frequency information of the LFM signal is determined.Simulation results show that this method can achieve high-accuracy parameter estimation for LFM signals at an SNR of-25 dB.展开更多
Flexible aqueous zinc-air batteries with high energy density and safety have garnered significant attention.Gel polymer electrolytes have emerged as the preferred option over conventional liquid electrolytes due to th...Flexible aqueous zinc-air batteries with high energy density and safety have garnered significant attention.Gel polymer electrolytes have emerged as the preferred option over conventional liquid electrolytes due to their ability to prevent electrolyte leakage.In this study,a composite PANa-PVP-TiO_(2)(NH_(2))hydrogel with high alkaline resistance and ionic conductivity is designed,where the inorganic TiO_(2)(NH_(2))nanoparticles are evenly distributed and integrated into the organic dual network of polyacrylate sodium and polyvinyl pyrrolidone.The organic-inorganic hybrid structure enhances the absorption and retention capabilities for electrolyte solution,leading to impressive ionic conductivity of the gel polymer electrolyte throughout the operation of flexible aqueous zinc-air batteries.Additionally,the incorporation of TiO_(2)(NH_(2))nanoparticles and the dual network construction effectively strengthen the mechanical strength and flexibility of the gel polymer electrolyte,suppressing by-products and zinc dendrite formation.The enhancements lead to the extended cycling longevity of zinc symmetric batteries and excellent power density,as well as the prolonged cycle life of flexible aqueous zinc-air batteries.展开更多
Karst groundwater plays a crucial role in sustaining water resources.However,the seasonal variations in hydrological cycling and quality remain insufficiently understood.This study integrated stable isotopes(δ^(2)H a...Karst groundwater plays a crucial role in sustaining water resources.However,the seasonal variations in hydrological cycling and quality remain insufficiently understood.This study integrated stable isotopes(δ^(2)H and δ^(18)O),entropy-weighted water quality indices(EWQI),and Bivariate Local Indicators of Spatial Association(BI-LISA)to investigate the seasonal groundwater dynamics and water quality evolution in the Baotu Spring karst groundwater system,a representative karst region in northern China.The seasonal sampling of 147 groundwater and river water samples revealed limited intra-annual isotopic variability.Groundwater recharge was primarily driven by wet season precipitation,and spatially heterogeneous mechanisms were identified.The area was divided into three groundwater subsystems(southern groundwater(SGW),central groundwater(CGW),and northern groundwater(NGW))based on isotopic(δ^(18)O and d-excess)and hydrogeological characteristics.SGW demonstrated the rapid atmospheric recharge with minimal evaporation,producing northward flow and isotopically depleted signatures.CGW reflected the mixed recharge sources(precipitation,SGW,and river water)with moderate evaporation during the southwest-to-northeast transport.NGW was mainly recharged by Yellow River infiltration,exhibiting riverine isotopic characteristics.Over 80%of the samples maintained the“Excellent”quality year-round,while localized Cl^(-),SO_(4)^(2-),and NO_(3)^(-)contamination existed.The dry-season water quality was influenced by anthropogenic inputs,whereas wet-season changes were governed by internal hydrogeochemical processes.BI-LISA revealed seasonal EWQI-isotope coupling.During the dry season,rapid SGW recharge transported surface pollutants,whereas river-fed CGW maintained water quality.During the wet season,δ^(18)O enrichment and quality degradation in CGW's eastern Yufu River zone were attributed to runoff-induced pollution,whereas SGW exhibited dilution-driven quality improvement.This study demonstrated that BI-LISA effectively addressed interpolation limitations and mapped pollution-hydrology-spatial interactions in karst systems to support sustainable water resource protection.展开更多
A genome-wide screen for mutants showing altered brassinosteroid （BR） sensitivity or bril-like phenotypes resulted in the identification of two new mutant alleles of TWISTED DWARF 1 （TWD1）, twd1-4, and twdl-5. Pre...A genome-wide screen for mutants showing altered brassinosteroid （BR） sensitivity or bril-like phenotypes resulted in the identification of two new mutant alleles of TWISTED DWARF 1 （TWD1）, twd1-4, and twdl-5. Pre- vious studies indicated that TWD1, also named as ULTRACURVATA 2 or FKBP42, associates with auxin efflux transporters and is essential for their biological functions. Although earlier reports showed that BR signaling is downregulated in twdl, how TWD1 is integrated in BR signaling has not been elucidated. Here, we provide ge- netic and biochemical evidence demonstrating that TWD1 interacts with the BR receptor BRI1 in vivo in a BR- independent manner. Further analyses indicated that TWD1 modulates the BR signal transduction not by altering ER quality control or protein abundance of BRI1; instead, TWD1 appears to be critical in BR- induced interaction of BRI1 and its co-receptor BAK1, as well as BR-induced phosphorylation of these two proteins. These results provide better understanding of the early events of the BR signaling pathway.展开更多
Brassinosteroids(BRs)are a group of steroidal phytohormones,playing critical roles in almost all physiological aspects during the life span of a plant.In Arabidopsis,BRs are perceived at the cell surface,triggering a ...Brassinosteroids(BRs)are a group of steroidal phytohormones,playing critical roles in almost all physiological aspects during the life span of a plant.In Arabidopsis,BRs are perceived at the cell surface,triggering a reversible phosphorylation-based signaling cascade that leads to the activation and nuclear accumulation of a family of transcription factors,represented by BES1 and BZR1.Protein famesylation is a type of post-translational modification,functioning in many important cellular processes.Previous studies demonstrated a role of famesylation in BR biosynthesis via regulating the endoplasmic reticulum localization of a key bassino-lide(BL)biosynthetic enzyme BR6ox2.Whether such a process is also involved in BR signaling is not understood.Here,we demonstrate that protein famesylation is involved in mediating BR signaling in Arabidopsis.A loss-of-function mutant of EN HANCED RESPONSE TO ABA 1(iERA1).encoding a(3 subunit of the protein famesyl transferase hoi oenzyme,can alter the BL sensitivity of bak1~4 from a reduced to a hypersensitive level,era 7 can partially rescue the BR defective phenotype of a hetero zygous mutant of bin2-1,a gain-of function mutant of BIN2 which encodes a negative regulator in the BR signaling.Our genetic and biochemical analyses revealed that ERA1 plays a significant role in regulating the protein stability of BES1.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61973037)。
文摘In view of the complexity of existing linear frequency modulation(LFM)signal parameter estimation methods and the poor antinoise performance and estimation accuracy under a low signal-to-noise ratio(SNR),a parameter estimation method for LFM signals with a Duffing oscillator based on frequency periodicity is proposed in this paper.This method utilizes the characteristic that the output signal of the Duffing oscillator excited by the LFM signal changes periodically with frequency,and the modulation period of the LFM signal is estimated by autocorrelation processing of the output signal of the Duffing oscillator.On this basis,the corresponding relationship between the reference frequency of the frequencyaligned Duffing oscillator and the frequency range of the LFM signal is analyzed by the periodic power spectrum method,and the frequency information of the LFM signal is determined.Simulation results show that this method can achieve high-accuracy parameter estimation for LFM signals at an SNR of-25 dB.
基金supported by the National Natural Science Foundation of China(Grant Nos.51872147,22136003)the Project of Hubei Provincial Department of Education(Grant No.D20221202)+1 种基金the 111 Project(Grant No.D20015)the Hubei Provincial Natural Science Foundation of China(Grant Nos.2022CFA065,2022CFB820).
文摘Flexible aqueous zinc-air batteries with high energy density and safety have garnered significant attention.Gel polymer electrolytes have emerged as the preferred option over conventional liquid electrolytes due to their ability to prevent electrolyte leakage.In this study,a composite PANa-PVP-TiO_(2)(NH_(2))hydrogel with high alkaline resistance and ionic conductivity is designed,where the inorganic TiO_(2)(NH_(2))nanoparticles are evenly distributed and integrated into the organic dual network of polyacrylate sodium and polyvinyl pyrrolidone.The organic-inorganic hybrid structure enhances the absorption and retention capabilities for electrolyte solution,leading to impressive ionic conductivity of the gel polymer electrolyte throughout the operation of flexible aqueous zinc-air batteries.Additionally,the incorporation of TiO_(2)(NH_(2))nanoparticles and the dual network construction effectively strengthen the mechanical strength and flexibility of the gel polymer electrolyte,suppressing by-products and zinc dendrite formation.The enhancements lead to the extended cycling longevity of zinc symmetric batteries and excellent power density,as well as the prolonged cycle life of flexible aqueous zinc-air batteries.
基金supported by the National Natural Science Foundation of China(Grant Nos.42430712,42302281)Jinan Science and Technology Bureau(2021GXRC070)。
文摘Karst groundwater plays a crucial role in sustaining water resources.However,the seasonal variations in hydrological cycling and quality remain insufficiently understood.This study integrated stable isotopes(δ^(2)H and δ^(18)O),entropy-weighted water quality indices(EWQI),and Bivariate Local Indicators of Spatial Association(BI-LISA)to investigate the seasonal groundwater dynamics and water quality evolution in the Baotu Spring karst groundwater system,a representative karst region in northern China.The seasonal sampling of 147 groundwater and river water samples revealed limited intra-annual isotopic variability.Groundwater recharge was primarily driven by wet season precipitation,and spatially heterogeneous mechanisms were identified.The area was divided into three groundwater subsystems(southern groundwater(SGW),central groundwater(CGW),and northern groundwater(NGW))based on isotopic(δ^(18)O and d-excess)and hydrogeological characteristics.SGW demonstrated the rapid atmospheric recharge with minimal evaporation,producing northward flow and isotopically depleted signatures.CGW reflected the mixed recharge sources(precipitation,SGW,and river water)with moderate evaporation during the southwest-to-northeast transport.NGW was mainly recharged by Yellow River infiltration,exhibiting riverine isotopic characteristics.Over 80%of the samples maintained the“Excellent”quality year-round,while localized Cl^(-),SO_(4)^(2-),and NO_(3)^(-)contamination existed.The dry-season water quality was influenced by anthropogenic inputs,whereas wet-season changes were governed by internal hydrogeochemical processes.BI-LISA revealed seasonal EWQI-isotope coupling.During the dry season,rapid SGW recharge transported surface pollutants,whereas river-fed CGW maintained water quality.During the wet season,δ^(18)O enrichment and quality degradation in CGW's eastern Yufu River zone were attributed to runoff-induced pollution,whereas SGW exhibited dilution-driven quality improvement.This study demonstrated that BI-LISA effectively addressed interpolation limitations and mapped pollution-hydrology-spatial interactions in karst systems to support sustainable water resource protection.
文摘A genome-wide screen for mutants showing altered brassinosteroid （BR） sensitivity or bril-like phenotypes resulted in the identification of two new mutant alleles of TWISTED DWARF 1 （TWD1）, twd1-4, and twdl-5. Pre- vious studies indicated that TWD1, also named as ULTRACURVATA 2 or FKBP42, associates with auxin efflux transporters and is essential for their biological functions. Although earlier reports showed that BR signaling is downregulated in twdl, how TWD1 is integrated in BR signaling has not been elucidated. Here, we provide ge- netic and biochemical evidence demonstrating that TWD1 interacts with the BR receptor BRI1 in vivo in a BR- independent manner. Further analyses indicated that TWD1 modulates the BR signal transduction not by altering ER quality control or protein abundance of BRI1; instead, TWD1 appears to be critical in BR- induced interaction of BRI1 and its co-receptor BAK1, as well as BR-induced phosphorylation of these two proteins. These results provide better understanding of the early events of the BR signaling pathway.
基金supported by the National Natural Sci-ence Foundation of China Grants 31720103902 ,32030005(to J.L.)111 Project B16022(to J.L.)the Funda-mental Research Funds for the Central Universities Grant no.lzujbky‐2020‐sp04(to J.L.),lzujbky‐2021‐kb05。
文摘Brassinosteroids(BRs)are a group of steroidal phytohormones,playing critical roles in almost all physiological aspects during the life span of a plant.In Arabidopsis,BRs are perceived at the cell surface,triggering a reversible phosphorylation-based signaling cascade that leads to the activation and nuclear accumulation of a family of transcription factors,represented by BES1 and BZR1.Protein famesylation is a type of post-translational modification,functioning in many important cellular processes.Previous studies demonstrated a role of famesylation in BR biosynthesis via regulating the endoplasmic reticulum localization of a key bassino-lide(BL)biosynthetic enzyme BR6ox2.Whether such a process is also involved in BR signaling is not understood.Here,we demonstrate that protein famesylation is involved in mediating BR signaling in Arabidopsis.A loss-of-function mutant of EN HANCED RESPONSE TO ABA 1(iERA1).encoding a(3 subunit of the protein famesyl transferase hoi oenzyme,can alter the BL sensitivity of bak1~4 from a reduced to a hypersensitive level,era 7 can partially rescue the BR defective phenotype of a hetero zygous mutant of bin2-1,a gain-of function mutant of BIN2 which encodes a negative regulator in the BR signaling.Our genetic and biochemical analyses revealed that ERA1 plays a significant role in regulating the protein stability of BES1.
