We present a unique case of crowned dens syndrome(CDS) that developed after endoscopic retrograde cholangiopancreatography(ERCP) in a patient who presented with fever and neck pain. Administration of non-steroidal ant...We present a unique case of crowned dens syndrome(CDS) that developed after endoscopic retrograde cholangiopancreatography(ERCP) in a patient who presented with fever and neck pain. Administration of non-steroidal anti-inflammatory drugs was extremely effective for relieving fever and neck pain, and in the improvement of inflammatory markers. To the best of our knowledge, this is the first case report of CDS caused by an ERCP procedure. In a patient with fever and neck pain after an ERCP procedure, CDS should be considered in the differential diagnosis.展开更多
Defined as an association of acute cervical pain and calcifications in the peri-odontoid space, crowned dens syndrome (CDS) is a major imaging manifestation of “coronary”. CDS is a rare but under-recognized cause of...Defined as an association of acute cervical pain and calcifications in the peri-odontoid space, crowned dens syndrome (CDS) is a major imaging manifestation of “coronary”. CDS is a rare but under-recognized cause of severe neck pain in older adults. As such, it is often misdiagnosed. So, we review the literature with particular attention to the clinical and radiological aspects of this syndrome.展开更多
The mixed LB film of mono crown ether substituted phthalocyanine(CPc)and potassium picrate(PiK)were prepared by adding potassium picrate in subphase.The pi-A isotherms show that the addition of PiK in subphase increas...The mixed LB film of mono crown ether substituted phthalocyanine(CPc)and potassium picrate(PiK)were prepared by adding potassium picrate in subphase.The pi-A isotherms show that the addition of PiK in subphase increases the orientation angles of phthalocyanine in monolayers.The absorption spectra revealed that the monolayer can be transferred to substrates easily.X-ray diffraction results show that the mixed film possesses the same thickness as that of pure phthalocyanine film.展开更多
Fu Shan(1607-1684),originally named Fu Dingchen(courtesy name:Fu Qingzhu),was from Yangqu County,Taiyuan Prefecture(present Taiyuan,Shanxi Province).His assumed name was Scarlet Taoist or Songqiao Old Man.Fu was a fam...Fu Shan(1607-1684),originally named Fu Dingchen(courtesy name:Fu Qingzhu),was from Yangqu County,Taiyuan Prefecture(present Taiyuan,Shanxi Province).His assumed name was Scarlet Taoist or Songqiao Old Man.Fu was a famous scholar in the period of the late Ming and early Qing Dynasties and he was a diligent student of Confucianism,religion,calligraphy,painting and medicine.He was highly esteemed in the history of Chinese culture and thought.Fu was skilled in phonology and critical interpretation of ancient texts.展开更多
Tree plantations are globally significant,and therefore,growth-related challenges cannot be ignored.Canopy structure and light environment influence the growth of plantations,but the precise relationship remains uncle...Tree plantations are globally significant,and therefore,growth-related challenges cannot be ignored.Canopy structure and light environment influence the growth of plantations,but the precise relationship remains unclear.We selected seven-year-old poplar plantations of varying cultivars planted various densities and measured their growth,canopy structure,and light environment.The findings indicate that poplar plantations of different cultivars and at different planting densities showed variations in leaf area index(LAI),average leaf angle(ALA),crown length(CL),length ratio(CLR),roundness(CR)and surface area(CSA),which directly or indirectly affect growth,resulting in disparities in their growing conditions.Crown roundness directly impacted growth,while LAI,CLR and ALA influenced growth indirectly by affecting intercellular carbon dioxide concentration.LAI and CLR had a positive effect;ALA had a negative one.Crown length and surface area directly and indirectly influenced growth by affecting photo synthetically active radiation and net photo synthetic rate,with direct impacts being more pronounced.This research has clarified the regulatory role of canopy structure in plantations growth,providing valuable insights for developing more effective management strategies.展开更多
Allometric equations are fundamental tools in ecological research and forestry management,widely used for estimating above-ground biomass and production,serving as the core foundations of dynamic vegetation models.Usi...Allometric equations are fundamental tools in ecological research and forestry management,widely used for estimating above-ground biomass and production,serving as the core foundations of dynamic vegetation models.Using global datasets from Tallo(a tree allometry and crown architecture database encompassing thousands of species)and TRY(a plant traits database),we fit B ayesian hierarchical models with three alternative functional forms(powerlaw,generalized Michaelis-Menten(gMM),and Weibull)to characterize how diameter at breast height(DBH),tree height(H),and crown radius(CR)scale with and without wood density as a species-level predictor.Our analysis revealed that the saturating Weibull function best captured the relationship between tree height and DBH in both functional groups,whereas the CR-DBH relationship was best predicted by a power-law function in angiosperms and by the gMM function in gymnosperms.Although including wood density did not significantly improve predictive performance,it revealed important ecological trade-offs:lighter-wood angiosperms achieve taller mature heights more rapidly,and denser wood promotes wider crown expansion across clades.We also found that accurately estimating DBH required considering both height and crown size,highlighting how these variables together distinguish trees of similar height but differing trunk diameters.Our results emphasize the importance of applying saturating functions for large trees to improve forest biomass estimates and show that wood density,though not always predictive at broad scales,helps illuminate the biomechanical and ecological constraints underlying diverse tree architectures.These findings offer practical pathways for integrating height-and crown-based metrics into existing carbon monitoring programs worldwide.展开更多
The photochromic process of an indolinospiropyran with a crown ether fragment (BN-BIPS) was studied by nanosecond laser photolysis technique. The results show that quinonic merocyanine B was formed via an excited sing...The photochromic process of an indolinospiropyran with a crown ether fragment (BN-BIPS) was studied by nanosecond laser photolysis technique. The results show that quinonic merocyanine B was formed via an excited singlet state from BN-BIPS; in acetonitrile solution, the transient absorption of merocyanine B showed an obvious decay while a new transient absorption at 440nm (from isomer C) was observed simultaneously. The decay of merocyanine B and the formation of isomer C (at 440nm) were accelerated in the presence of alkali metal cation. In contrast, the formation of isomer C was not observed in spiropyran without a crown ether fragment: BIPS.展开更多
Dear Editor,Population size is a crucial indicator in evaluating the conservation status of a species.Understanding the patterns of population fluctuation and the distribution range of endangered species is important ...Dear Editor,Population size is a crucial indicator in evaluating the conservation status of a species.Understanding the patterns of population fluctuation and the distribution range of endangered species is important for biodiversity conservation,which contributes to ecosystem functioning(Li et al.,2019;Eisenhauer,2022).展开更多
The computations of the electronic structures and properties of a novel crowned [60] fulleropyrrolidine (CFP) were performed by means of AM1 methods. It has been indicated that CFP has four isomers in which the dihedr...The computations of the electronic structures and properties of a novel crowned [60] fulleropyrrolidine (CFP) were performed by means of AM1 methods. It has been indicated that CFP has four isomers in which the dihedral angle between phenyl group and pyrrolidine ring is around ± 90°. The study of electronic structures showed that the energy levels of frontier orbitals are determined mainly by C60. C60 acted as an electronic acceptor, whereas crown ether acted as an electronic donor, which implies that there exists intramolecular charge transfer effect in this molecule. The study of nonlinear optical properties implied that the hyperpolaritability of CFP can match that ofρ-ni-troaniline. In the meantime, the hyperpolariubility properties of CFP could be influenced by the orientation of crown ether moiety.展开更多
In the dozen years since returning to her birth country,Helen Feng has been a vital force in the Mainland music scene.As a cuttural commentator as host of The Rock Show.As a creative entrepreneur with the FakeMusicMed...In the dozen years since returning to her birth country,Helen Feng has been a vital force in the Mainland music scene.As a cuttural commentator as host of The Rock Show.As a creative entrepreneur with the FakeMusicMedia collective she co-founded.And as the front woman for three seminal groups.Often dubbed the'Queen of Beiing rock,'she's closing in on her crowning achievement,as her current group Nova Heart storms through the country to support their highly anticipated self-titled debut album.展开更多
In the dozen years since returning to her birth country,Helen Feng has been a vital force in the Mainland music scene:as a cultural commentator and host of The Rock Show,a creative entrepreneur with the FakeMusicMedia...In the dozen years since returning to her birth country,Helen Feng has been a vital force in the Mainland music scene:as a cultural commentator and host of The Rock Show,a creative entrepreneur with the FakeMusicMedia collective she co-founded;and the frontwoman for three seminal groups.Often dubbed the'Queen of Beijing Rock;she's closing in on her crowning achievement,as her current group Nova Heart storms through the country to support their highly anticipated self-titled debut album.展开更多
Recently,three red-crowned crane couples at Wuhan Zoo became the proud parents of six newborn chicks.Female red-crowned cranes in the wild commonly give birth to two babies and usually only one survives.In order to im...Recently,three red-crowned crane couples at Wuhan Zoo became the proud parents of six newborn chicks.Female red-crowned cranes in the wild commonly give birth to two babies and usually only one survives.In order to improve their survival rate,the zoo has arranged for the"father"to live in a cage with one of the babies and the"mother"in an adjacent cage with the other.展开更多
Accurate crown control is paramount for ensuring the quality of hot-rolled strip products.Given the multitude of influencing parameters and the intricate coupling and genetic relationships among them,the conventional ...Accurate crown control is paramount for ensuring the quality of hot-rolled strip products.Given the multitude of influencing parameters and the intricate coupling and genetic relationships among them,the conventional crown control method is no longer sufficient to meet the precision requirements of schedule-free rolling.To address this limitation,an optimization framework for hot-rolled strip crown control was developed based on model-driven digital twin(MDDT).This framework enhances the strip crown control precision by facilitating collaborative operations among physical entities,virtual models,and functional application layers.In virtual modeling,a data-driven approach that integrates the extreme gradient boosting and the improved Harris hawk optimization algorithm was firstly proposed to fit the relationship between key process parameters and strip crown,and a global-local collaborative training strategy was proposed to enhance the model adaptability to diverse working conditions.Subsequently,the influence of crucial process factors on the virtual model was examined through model responses.Furthermore,a novel optimization mode for crown control based on MDDT was established by aligning and reconstructing both the physical and virtual models,thereby enhancing the crown control precision.Finally,data trials were conducted to validate the effectiveness of the proposed framework.The results indicated that the proposed method exhibited satisfactory performance and could be effectively utilized to improve the crown control precision.展开更多
Boom in creative cultural products is boosting Chinese museums.The National Museum of China’s phoenix crown magnet,considered the jewel in the crown of the country’s cultural souvenirs,hit a milestone on 25 March,se...Boom in creative cultural products is boosting Chinese museums.The National Museum of China’s phoenix crown magnet,considered the jewel in the crown of the country’s cultural souvenirs,hit a milestone on 25 March,selling over 1 million units in just eight months and six days.Since last autumn,visitors have been queuing before dawn to get their hands on this star product whenever the museum is open.展开更多
The separation of lithium isotopes (^(6)Li and ^(7)Li) is of great importance for the nuclear industry.The lithium amalgam method is the only lithium isotopes separation process in industry,and the extensive use of me...The separation of lithium isotopes (^(6)Li and ^(7)Li) is of great importance for the nuclear industry.The lithium amalgam method is the only lithium isotopes separation process in industry,and the extensive use of mercury has raised concerns about its potential environmental hazards,which have prompted the search for more efficient and environmentally friendly alternatives.Crown ethers can bind lithium ions highly selectively and separate lithium isotopes effectively.A chemical exchange-based lithium isotopes separation method using crown ether decorated materials could be a viable and cost-effective alternative to the lithium amalgam method.In this review,we provide a systematic summary of the recent advances in lithium isotopes separation using crown ethers decorated materials.展开更多
The authors regret that the declaration of Acknowledgement as below is missing in the paper:AcknowledgementWe are grateful to the Department of Biology and Postgraduate Sciences-Biology of the Universidad del Valle,Ca...The authors regret that the declaration of Acknowledgement as below is missing in the paper:AcknowledgementWe are grateful to the Department of Biology and Postgraduate Sciences-Biology of the Universidad del Valle,Cali-Colombia for their support of the project;to Wilmar Torres MSc.for his statistical advice;to the biologist Helen Burnham MSc.for the translation of the document;to Isabel Castro and all the members of the Ornithology and Animal Behaviour Laboratory-OYCA of Universidad del Valle for their invaluable support in the field.We sincerely thank the anonymous re-viewers for their invaluable feedback and contributions to our manuscript.展开更多
Anion exchange membrane(AEM)fuel cells require membranes with a balance of high conductivity and durability.In this work,a novel bi-crown-ether modified piperidine structure was designed and synthesized,which was then...Anion exchange membrane(AEM)fuel cells require membranes with a balance of high conductivity and durability.In this work,a novel bi-crown-ether modified piperidine structure was designed and synthesized,which was then introduced into the side chain of poly(arylene piperidinium),making a unique bi-crown-ether modified bi-piperidinium side chain grafted polymer for AEM fabrication.The double crown ether units enhanced cation–water interactions and promoted microphase separation,thereby forming efficient hydroxide ion transport channels.The resulting membrane exhibited high water uptake,well-defined ion clusters,and a hydroxide conductivity of 123 mS cm^(-1) at 80℃ with an ion exchange capacity(IEC)of 1.56 mmol g^(-1).After alkaline treatment in 1 M NaOH at 80℃ for 960 h,the membrane retained~85%of its initial conductivity,demonstrating excellent chemical stability.In H2/O2 fuel cell tests at 60℃ ,the membrane achieved a peak power density of 558 mW cm-2 at 1040 mA cm-2.These findings highlight the potential of bi-crown-ether modified piperidinium side chain grafting as an effective strategy to enhance ion conduction properties of AEMs for fuel cell applications.展开更多
In permanently uneven-aged forests, continuous ingrowth of recruitment into higher stand layers is a critical process for the formation and maintenance of differentiated stand structures. This study analyses the abund...In permanently uneven-aged forests, continuous ingrowth of recruitment into higher stand layers is a critical process for the formation and maintenance of differentiated stand structures. This study analyses the abundance and diversity of recruitment(diameter at breast high(DBH) 0.1–4 cm) across 241 research plots in 11 structurally differentiated Norway spruce(silver fir)-dominated forest stands distributed at altitudes between 500 and 1,440 m a.s.l. The influence of light conditions and lateral competition characteristics on the height increment and crown architecture of recruitment was investigated in detail for 352 Norway spruce and 361 silver fir trees. Light-related variables were confirmed to directly affect the recruitment distribution only to a limited extent. Under relatively low light conditions in montane stands, silver fir reached higher height increments than Norway spruce. The better adaptation of silver fir to shaded conditions was reflected also in its higher apical dominance ratio compared to Norway spruce. The height increment and apical dominance ratio of Norway spruce and silver fir recruitment were positively correlated with indirect radiation, DBH, and relative crown length(RCL), but not with lateral competition. These results confirm that the regulation of light conditions in permanently unevenaged stands is crucial for the growth dynamics of recruitment, as well as for the future proportions of Norway spruce and silver fir in mixed, structurally diverse stands.展开更多
Branch size is a crucial characteristic,closely linked to both tree growth and wood quality.A review of existing branch size models reveals various approaches,but the ability to estimate branch diameter and length wit...Branch size is a crucial characteristic,closely linked to both tree growth and wood quality.A review of existing branch size models reveals various approaches,but the ability to estimate branch diameter and length within the same whorl remains underexplored.In this study,a total of 77 trees were sampled from Northeast China to model the vertical distribution of branch diameter and length within each whorl along the crown.Several commonly used functions were taken as the alternative model forms,and the quantile regression method was employed and compared with the classical two-step modeling approach.The analysis incorporated stand,tree,and competition factors,with a particular focus on how these factors influence branches of varying sizes.The modified Weibull function was chosen as the optimal model,due to its excellent performance across all quantiles.Eight quantile regression curves(ranging from 0.20 to 0.85)were combined to predict branch diameter,while seven curves(ranging from 0.20 to 0.80)were used for branch length.The results showed that the quantile regression method outperformed the classical approach at model fitting and validation,likely due to its ability to estimate different rates of change across the entire branch size distribution.Lager branches in each whorl were more sensitive to changes in DBH,crown length(CL),crown ratio(CR)and dominant tree height(H_(dom)),while slenderness(HDR)more effectively influenced small and medium-sized branches.The effect of stand basal area(BAS)was relatively consistent across different branch sizes.The findings indicate that quantile regression is a good way not only a more accurate method for predicting branch size but also a valuable tool for understanding how branch growth responds to stand and tree factors.The models developed in this study are prepared to be further integrated into tree growth and yield simulation system,contributing to the assessment and promotion of wood quality.展开更多
文摘We present a unique case of crowned dens syndrome(CDS) that developed after endoscopic retrograde cholangiopancreatography(ERCP) in a patient who presented with fever and neck pain. Administration of non-steroidal anti-inflammatory drugs was extremely effective for relieving fever and neck pain, and in the improvement of inflammatory markers. To the best of our knowledge, this is the first case report of CDS caused by an ERCP procedure. In a patient with fever and neck pain after an ERCP procedure, CDS should be considered in the differential diagnosis.
文摘Defined as an association of acute cervical pain and calcifications in the peri-odontoid space, crowned dens syndrome (CDS) is a major imaging manifestation of “coronary”. CDS is a rare but under-recognized cause of severe neck pain in older adults. As such, it is often misdiagnosed. So, we review the literature with particular attention to the clinical and radiological aspects of this syndrome.
基金the National Natural Science Foundation of China for the financial support(project No.29733100).
文摘The mixed LB film of mono crown ether substituted phthalocyanine(CPc)and potassium picrate(PiK)were prepared by adding potassium picrate in subphase.The pi-A isotherms show that the addition of PiK in subphase increases the orientation angles of phthalocyanine in monolayers.The absorption spectra revealed that the monolayer can be transferred to substrates easily.X-ray diffraction results show that the mixed film possesses the same thickness as that of pure phthalocyanine film.
文摘Fu Shan(1607-1684),originally named Fu Dingchen(courtesy name:Fu Qingzhu),was from Yangqu County,Taiyuan Prefecture(present Taiyuan,Shanxi Province).His assumed name was Scarlet Taoist or Songqiao Old Man.Fu was a famous scholar in the period of the late Ming and early Qing Dynasties and he was a diligent student of Confucianism,religion,calligraphy,painting and medicine.He was highly esteemed in the history of Chinese culture and thought.Fu was skilled in phonology and critical interpretation of ancient texts.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFD2201203)the financial support of the National Natural Science Foundation of China(32001311)。
文摘Tree plantations are globally significant,and therefore,growth-related challenges cannot be ignored.Canopy structure and light environment influence the growth of plantations,but the precise relationship remains unclear.We selected seven-year-old poplar plantations of varying cultivars planted various densities and measured their growth,canopy structure,and light environment.The findings indicate that poplar plantations of different cultivars and at different planting densities showed variations in leaf area index(LAI),average leaf angle(ALA),crown length(CL),length ratio(CLR),roundness(CR)and surface area(CSA),which directly or indirectly affect growth,resulting in disparities in their growing conditions.Crown roundness directly impacted growth,while LAI,CLR and ALA influenced growth indirectly by affecting intercellular carbon dioxide concentration.LAI and CLR had a positive effect;ALA had a negative one.Crown length and surface area directly and indirectly influenced growth by affecting photo synthetically active radiation and net photo synthetic rate,with direct impacts being more pronounced.This research has clarified the regulatory role of canopy structure in plantations growth,providing valuable insights for developing more effective management strategies.
基金supported by the Xingdian Talent Support Program of Yunnan Province(E5YNR03B01)the Xishuangbanna State Rainforest Talent Support Program(E4BN041B01)the CAS President’s International Fellowship Initiative(2020FYB0003)。
文摘Allometric equations are fundamental tools in ecological research and forestry management,widely used for estimating above-ground biomass and production,serving as the core foundations of dynamic vegetation models.Using global datasets from Tallo(a tree allometry and crown architecture database encompassing thousands of species)and TRY(a plant traits database),we fit B ayesian hierarchical models with three alternative functional forms(powerlaw,generalized Michaelis-Menten(gMM),and Weibull)to characterize how diameter at breast height(DBH),tree height(H),and crown radius(CR)scale with and without wood density as a species-level predictor.Our analysis revealed that the saturating Weibull function best captured the relationship between tree height and DBH in both functional groups,whereas the CR-DBH relationship was best predicted by a power-law function in angiosperms and by the gMM function in gymnosperms.Although including wood density did not significantly improve predictive performance,it revealed important ecological trade-offs:lighter-wood angiosperms achieve taller mature heights more rapidly,and denser wood promotes wider crown expansion across clades.We also found that accurately estimating DBH required considering both height and crown size,highlighting how these variables together distinguish trees of similar height but differing trunk diameters.Our results emphasize the importance of applying saturating functions for large trees to improve forest biomass estimates and show that wood density,though not always predictive at broad scales,helps illuminate the biomechanical and ecological constraints underlying diverse tree architectures.These findings offer practical pathways for integrating height-and crown-based metrics into existing carbon monitoring programs worldwide.
文摘The photochromic process of an indolinospiropyran with a crown ether fragment (BN-BIPS) was studied by nanosecond laser photolysis technique. The results show that quinonic merocyanine B was formed via an excited singlet state from BN-BIPS; in acetonitrile solution, the transient absorption of merocyanine B showed an obvious decay while a new transient absorption at 440nm (from isomer C) was observed simultaneously. The decay of merocyanine B and the formation of isomer C (at 440nm) were accelerated in the presence of alkali metal cation. In contrast, the formation of isomer C was not observed in spiropyran without a crown ether fragment: BIPS.
基金supported by the National Natural Science Foundation of China(32360251,31660608,and 31360521)the Jiangxi Forestry Science and Technology Innovation Project(202213).
文摘Dear Editor,Population size is a crucial indicator in evaluating the conservation status of a species.Understanding the patterns of population fluctuation and the distribution range of endangered species is important for biodiversity conservation,which contributes to ecosystem functioning(Li et al.,2019;Eisenhauer,2022).
基金Project supported by the National Natural Science Foundation of China (Grant No. 29671030)
文摘The computations of the electronic structures and properties of a novel crowned [60] fulleropyrrolidine (CFP) were performed by means of AM1 methods. It has been indicated that CFP has four isomers in which the dihedral angle between phenyl group and pyrrolidine ring is around ± 90°. The study of electronic structures showed that the energy levels of frontier orbitals are determined mainly by C60. C60 acted as an electronic acceptor, whereas crown ether acted as an electronic donor, which implies that there exists intramolecular charge transfer effect in this molecule. The study of nonlinear optical properties implied that the hyperpolaritability of CFP can match that ofρ-ni-troaniline. In the meantime, the hyperpolariubility properties of CFP could be influenced by the orientation of crown ether moiety.
文摘In the dozen years since returning to her birth country,Helen Feng has been a vital force in the Mainland music scene.As a cuttural commentator as host of The Rock Show.As a creative entrepreneur with the FakeMusicMedia collective she co-founded.And as the front woman for three seminal groups.Often dubbed the'Queen of Beiing rock,'she's closing in on her crowning achievement,as her current group Nova Heart storms through the country to support their highly anticipated self-titled debut album.
文摘In the dozen years since returning to her birth country,Helen Feng has been a vital force in the Mainland music scene:as a cultural commentator and host of The Rock Show,a creative entrepreneur with the FakeMusicMedia collective she co-founded;and the frontwoman for three seminal groups.Often dubbed the'Queen of Beijing Rock;she's closing in on her crowning achievement,as her current group Nova Heart storms through the country to support their highly anticipated self-titled debut album.
文摘Recently,three red-crowned crane couples at Wuhan Zoo became the proud parents of six newborn chicks.Female red-crowned cranes in the wild commonly give birth to two babies and usually only one survives.In order to improve their survival rate,the zoo has arranged for the"father"to live in a cage with one of the babies and the"mother"in an adjacent cage with the other.
基金financially supported by the National Key Research and Development Program of China(Grant No.2023YFB3710204)Guangxi Science and Technology Major Program(Grant No.AA23023028-1)+1 种基金Natural Science Foundation of Heilongjiang Province of China for Distinguished Young Scientists(Grant No.JQ2022E007)Xinjiang Production and Construction Corps Science and Technology Plan(Grant No.2023AA003).
文摘Accurate crown control is paramount for ensuring the quality of hot-rolled strip products.Given the multitude of influencing parameters and the intricate coupling and genetic relationships among them,the conventional crown control method is no longer sufficient to meet the precision requirements of schedule-free rolling.To address this limitation,an optimization framework for hot-rolled strip crown control was developed based on model-driven digital twin(MDDT).This framework enhances the strip crown control precision by facilitating collaborative operations among physical entities,virtual models,and functional application layers.In virtual modeling,a data-driven approach that integrates the extreme gradient boosting and the improved Harris hawk optimization algorithm was firstly proposed to fit the relationship between key process parameters and strip crown,and a global-local collaborative training strategy was proposed to enhance the model adaptability to diverse working conditions.Subsequently,the influence of crucial process factors on the virtual model was examined through model responses.Furthermore,a novel optimization mode for crown control based on MDDT was established by aligning and reconstructing both the physical and virtual models,thereby enhancing the crown control precision.Finally,data trials were conducted to validate the effectiveness of the proposed framework.The results indicated that the proposed method exhibited satisfactory performance and could be effectively utilized to improve the crown control precision.
文摘Boom in creative cultural products is boosting Chinese museums.The National Museum of China’s phoenix crown magnet,considered the jewel in the crown of the country’s cultural souvenirs,hit a milestone on 25 March,selling over 1 million units in just eight months and six days.Since last autumn,visitors have been queuing before dawn to get their hands on this star product whenever the museum is open.
基金support from the National Natural Science Foundation of China (Grant No.U21B2094 and Grant No.U2067212)。
文摘The separation of lithium isotopes (^(6)Li and ^(7)Li) is of great importance for the nuclear industry.The lithium amalgam method is the only lithium isotopes separation process in industry,and the extensive use of mercury has raised concerns about its potential environmental hazards,which have prompted the search for more efficient and environmentally friendly alternatives.Crown ethers can bind lithium ions highly selectively and separate lithium isotopes effectively.A chemical exchange-based lithium isotopes separation method using crown ether decorated materials could be a viable and cost-effective alternative to the lithium amalgam method.In this review,we provide a systematic summary of the recent advances in lithium isotopes separation using crown ethers decorated materials.
文摘The authors regret that the declaration of Acknowledgement as below is missing in the paper:AcknowledgementWe are grateful to the Department of Biology and Postgraduate Sciences-Biology of the Universidad del Valle,Cali-Colombia for their support of the project;to Wilmar Torres MSc.for his statistical advice;to the biologist Helen Burnham MSc.for the translation of the document;to Isabel Castro and all the members of the Ornithology and Animal Behaviour Laboratory-OYCA of Universidad del Valle for their invaluable support in the field.We sincerely thank the anonymous re-viewers for their invaluable feedback and contributions to our manuscript.
基金supported by the following research grant.The Creative Group Fund of National Natural Science Foundation of China(Grant no.22021005)the Fund of National Natural Science Foundation of China(Grant no.22075037)HEC for National Research Program for Universities(NRPU)Project no.14840.
文摘Anion exchange membrane(AEM)fuel cells require membranes with a balance of high conductivity and durability.In this work,a novel bi-crown-ether modified piperidine structure was designed and synthesized,which was then introduced into the side chain of poly(arylene piperidinium),making a unique bi-crown-ether modified bi-piperidinium side chain grafted polymer for AEM fabrication.The double crown ether units enhanced cation–water interactions and promoted microphase separation,thereby forming efficient hydroxide ion transport channels.The resulting membrane exhibited high water uptake,well-defined ion clusters,and a hydroxide conductivity of 123 mS cm^(-1) at 80℃ with an ion exchange capacity(IEC)of 1.56 mmol g^(-1).After alkaline treatment in 1 M NaOH at 80℃ for 960 h,the membrane retained~85%of its initial conductivity,demonstrating excellent chemical stability.In H2/O2 fuel cell tests at 60℃ ,the membrane achieved a peak power density of 558 mW cm-2 at 1040 mA cm-2.These findings highlight the potential of bi-crown-ether modified piperidinium side chain grafting as an effective strategy to enhance ion conduction properties of AEMs for fuel cell applications.
基金supported by the Scientific Grant Agency of Ministry of Education,Science,Research and Sport of the Slovak Republic (project VEGA 1/0183/25)by the Slovak Research and Development Agency under the Contract No. APVV-21-0199 and APVV-19-0183
文摘In permanently uneven-aged forests, continuous ingrowth of recruitment into higher stand layers is a critical process for the formation and maintenance of differentiated stand structures. This study analyses the abundance and diversity of recruitment(diameter at breast high(DBH) 0.1–4 cm) across 241 research plots in 11 structurally differentiated Norway spruce(silver fir)-dominated forest stands distributed at altitudes between 500 and 1,440 m a.s.l. The influence of light conditions and lateral competition characteristics on the height increment and crown architecture of recruitment was investigated in detail for 352 Norway spruce and 361 silver fir trees. Light-related variables were confirmed to directly affect the recruitment distribution only to a limited extent. Under relatively low light conditions in montane stands, silver fir reached higher height increments than Norway spruce. The better adaptation of silver fir to shaded conditions was reflected also in its higher apical dominance ratio compared to Norway spruce. The height increment and apical dominance ratio of Norway spruce and silver fir recruitment were positively correlated with indirect radiation, DBH, and relative crown length(RCL), but not with lateral competition. These results confirm that the regulation of light conditions in permanently unevenaged stands is crucial for the growth dynamics of recruitment, as well as for the future proportions of Norway spruce and silver fir in mixed, structurally diverse stands.
基金supported by the Young Scientists Fund of the National Key R&D Program of China(No.2022YFD2201800)the Youth Science Fund Program of National Natural Science Foundation of China(No.32301581)+2 种基金the Joint Funds for Regional Innovation and Development of the National Natural Science Foundation of China(No.U21A20244)the China Postdoctoral Science Foundation(No.2024M750383)the Heilongjiang Touyan Innovation Team Program(Technology Development Team for High-Efficiency Silviculture of Forest Resources).
文摘Branch size is a crucial characteristic,closely linked to both tree growth and wood quality.A review of existing branch size models reveals various approaches,but the ability to estimate branch diameter and length within the same whorl remains underexplored.In this study,a total of 77 trees were sampled from Northeast China to model the vertical distribution of branch diameter and length within each whorl along the crown.Several commonly used functions were taken as the alternative model forms,and the quantile regression method was employed and compared with the classical two-step modeling approach.The analysis incorporated stand,tree,and competition factors,with a particular focus on how these factors influence branches of varying sizes.The modified Weibull function was chosen as the optimal model,due to its excellent performance across all quantiles.Eight quantile regression curves(ranging from 0.20 to 0.85)were combined to predict branch diameter,while seven curves(ranging from 0.20 to 0.80)were used for branch length.The results showed that the quantile regression method outperformed the classical approach at model fitting and validation,likely due to its ability to estimate different rates of change across the entire branch size distribution.Lager branches in each whorl were more sensitive to changes in DBH,crown length(CL),crown ratio(CR)and dominant tree height(H_(dom)),while slenderness(HDR)more effectively influenced small and medium-sized branches.The effect of stand basal area(BAS)was relatively consistent across different branch sizes.The findings indicate that quantile regression is a good way not only a more accurate method for predicting branch size but also a valuable tool for understanding how branch growth responds to stand and tree factors.The models developed in this study are prepared to be further integrated into tree growth and yield simulation system,contributing to the assessment and promotion of wood quality.
