The digitisation of musical manuscripts has transformed them from static heritage assets into dynamic data capital.This study explores how digitisation enhances the cultural value of musical manuscripts in low-resourc...The digitisation of musical manuscripts has transformed them from static heritage assets into dynamic data capital.This study explores how digitisation enhances the cultural value of musical manuscripts in low-resource contexts,focusing on Kyrgyz instrumental traditions(küü).Grounded in the SCP-R(Structure,Culture,Performance,and Resources)model,we analyse digitisation's impact through structural,cultural,performance,and resource dimensions.We propose a three-stage"embed–reconstruct–transform"framework,leveraging 12,400 folios and 2,300 hours of audio from the Kyrgyz National Conservatory.A Kyrgyz-tuned Transformer(MusicKG-T)trained with nomadic-path contrastive learning(CMCL-Kyrgyz)demonstrates that digitisation improves accessibility and usability,significantly increasing cultural and economic value.Findings offer a reproducible workflow for Silk-Road archives and highlight implications for music education and cultural policy.Future research should validate applicability to vocal traditions and other regions.展开更多
The Three Gorges Region(TGR)of the Yangtze River basin exhibited warm and dry climatic characteristics in 2024.The annual mean temperature in the TGR was 18.6℃,which was 1.2℃above normal and marked the highest level...The Three Gorges Region(TGR)of the Yangtze River basin exhibited warm and dry climatic characteristics in 2024.The annual mean temperature in the TGR was 18.6℃,which was 1.2℃above normal and marked the highest level since 1961.All four seasons were warmer than normal,with spring and autumn both recording their highest temperatures since 1961.Additionally,the TGR recorded 57.2 high-temperature days in 2024,reaching a historic high since 1961 and exceeding the previous record set in 2022 by 2.4 days.Annual rainfall was 11.2%below normal,with spring,summer,and autumn all being drier than normal.However,the number of heavy rain days was slightly higher than normal.The annual mean wind speed in the TGR ranked as the second-highest since 1961,only slightly lower than in 2022.The annual mean relative humidity was below normal and the number of fog days across large areas of the TGR decreased compared to 2023.In 2024,the TGR experienced extreme high-temperature events characterized by exceptional intensity and prolonged duration,accompanied by generally severe meteorological drought conditions.During the year,the TGR also experienced frequent and intense cooling events,an early onset of heavy rainfall(including severe convective weather),and exceptionally extreme rainstorm events.展开更多
The year 2024 witnessed remarkable climatic anomalies across China,characterized by pronounced warm and wet conditions.The annual mean temperature soared to a record high since 1951,with seasonal temperatures in sprin...The year 2024 witnessed remarkable climatic anomalies across China,characterized by pronounced warm and wet conditions.The annual mean temperature soared to a record high since 1951,with seasonal temperatures in spring,summer,and autumn all exceeding historical extremes.Meanwhile,the annual precipitation ranked as the fourth highest on record,with all four seasons experiencing above-average rainfall.Notably,the Yangtze River Basin and Jiangnan region encountered their most intense precipitation event since 1961.Extreme weather events were particularly striking:An unusually early and severe heatwave swept through central and eastern China,becoming the second most intense high-temperature event in recorded history.Autumn typhoon activity also displayed exceptional intensity,with Typhoon Yagi triggering significant impacts in Hainan,Guangdong,and Guangxi.Although drought conditions were generally mild overall,notable seasonal and regional disparities emerged,especially in the winter–spring droughts affecting southwestern China.Conversely,cold outbreaks occurred more frequently than usual,and convective weather events exhibited heightened activity.Moreover,dust storm activity remained relatively limited.展开更多
In 2020,the average air temperature in the Three Gorges Region(TGR)of the Yangtze River basin was 17.2℃,which was close to normal,there were exceptionally fewer days than normal with high temperatures,and the high-te...In 2020,the average air temperature in the Three Gorges Region(TGR)of the Yangtze River basin was 17.2℃,which was close to normal,there were exceptionally fewer days than normal with high temperatures,and the high-temperature events mainly occurred in August.Meanwhile,the average precipitation was 1530.8 mm,which was a remarkable 29%more than usual,and the second-highest since 1961.The precipitation was obviously above-normal in summer,and the precipitation in both June and July was the second-highest of the same period in history.The average number of rainstorm days was higher than normal,and the second-highest since 1961.The average wind speed in the TGR was apparently higher than normal;the average relative humidity was slightly higher than normal;and there were no instances of acid rain,with the rain acidity showing a significant weakening trend over the previous 15 years.In the summer of 2020,the TGR experienced heavy rainstorms and flood disasters.Analysis shows that the frequent southward movement of cold air and abundant warm water vapor from the southwest were the direct causes of the abnormally high precipitation in the TGR from June to July.After the spring of 2020,the continuously high sea surface temperature in the Indian Ocean led to a continuously strong western Pacific subtropical high and its average location being situated more to the south than normal,which might have been an important cause for the abnormal climate conditions in the Yangtze River basin from June to July.展开更多
This report provides a broad overview of the climate and the major weather and climate events over the Three Gorges Region of the Yangtze River(TGR)in 2019.The year 2019,a 0.3℃ warmer year than normal,had a colder wi...This report provides a broad overview of the climate and the major weather and climate events over the Three Gorges Region of the Yangtze River(TGR)in 2019.The year 2019,a 0.3℃ warmer year than normal,had a colder winter and warmer spring,summer,and autumn.Annual precipitation in 2019 was 13%less than normal.Below average normal rainfall amounts were received in all four seasons,with 28%and 16%less-than-normal in winter and summer,respectively.The annual mean wind speed in the TGR was higher than normal,and relative humidity was near normal for all four seasons.The intensity of acid rain in 2019 was the weakest since 1999.The major climate events and meteorological disasters in the TGR in 2019 included heat waves,drought,and rainstorms.Heat waves occurred frequently and persisted for long durations.Summer and autumn drought occurred in central and eastern regions of the TGR.The autumn rains of West China occurred earlier this year,which brought much more rainfall than normal in central and western regions of the TGR.展开更多
Based on daily observation data in the Three Gorges Region(TGR)of the Yangtze River Basin and global reanalysis data,the authors analyzed the climate characteristics and associated temporal variations in the main mete...Based on daily observation data in the Three Gorges Region(TGR)of the Yangtze River Basin and global reanalysis data,the authors analyzed the climate characteristics and associated temporal variations in the main meteorological factors in 2021,as well as the year’s climatic events and meteorological disasters.The 2021 average temperature was 0.2℃above the 1991-2020 average and the 13 th-warmest year since 1961.Seasonally,winter and autumn were both warmer than usual.The annual mean precipitation was 12.8%above normal,and most regions experienced abundant rainfall throughout the year.The seasonal variation in precipitation was significant and the TGR had a wetter-than-normal spring and summer.The number of rainstorm days was higher than normal;the wind speed was above normal;and the relative humidity was higher than normal.In terms of rain acidity,2021 was tied with 2020 as the lowest since 1999.From mid-September to early October 2021,the TGR experienced exceptional high-temperature weather,which was driven by abnormal activity of mid-and high-latitude atmospheric circulation over the Eurasian continent and the western Pacific subtropical high(WPSH).In addition,a strong blocking high over the Ural Mountains accompanied by intense mid-latitude westerly winds prevented cyclonic disturbances from extending to the subtropical region.As a result,under the combined effect of the weaker-than-normal cold-air activities and the anomalous WPSH,the TGR experienced extreme high-temperature weather during early autumn 2021.展开更多
Highly efficient and stable bifunctional electrocatalysts that can be used for large-current-density electrolysis of alkaline seawater are highly desirable for carbon-neutral economies,but their facile and controllabl...Highly efficient and stable bifunctional electrocatalysts that can be used for large-current-density electrolysis of alkaline seawater are highly desirable for carbon-neutral economies,but their facile and controllable synthesis remains a challenge.Here,self-assembled ultralow Ru,Ni-doped Fe_(2)O_(3) with a lily shaped morphology was synthesized on iron foam(RuNi-Fe_(2)O_(3)/IF)via a facile one-step hydrothermal process,in which the intact lily shaped RuNi-Fe_(2)O_(3)/IF was obtained by adjusting the ratio of Ru/Ni.Benefitting from the Ru/Ni chemical substitution,the as-synthesized RuNi-Fe_(2)O_(3)/IF can act as free-standing dual-function electrodes that are applied to electrocatalysis for the hydrogen evolution(HER)and oxygen evolution reactions(OER)in 1.0 mol L^(-1) KOH,requiring an overpotential of 75.0 mV to drive 100 mA cm^(-2) for HER and 329.0 mV for OER.Moreover,the overall water splitting catalyzed by RuNi-Fe_(2)O_(3)/IF only demands ultralow cell voltages of 1.66 and 1.73 V to drive 100 mA cm^(-2) in 1.0 mol L^(-1) KOH and 1.0 mol L^(-1) KOH seawater electrolytes,respectively.The electrodes show remarkable long-term durability,maintaining current densities exceeding 100 mA cm^(-2) for more than 100 h and thus outperforming the two-electrode system composed of noble catalysts.This work provides an efficient,economical method to synthesize self-standing bifunctional electrodes for large-current-density alkaline seawater electrolysis,which is of significant importance for ecological protection and energy exploitation.展开更多
Based on daily observation data of the Three Gorges Region(TGR)of the Yangtze River basin and global reanalysis data,the climate characteristics,climate events,and meteorological disasters of the TGR in 2022 and 2023 ...Based on daily observation data of the Three Gorges Region(TGR)of the Yangtze River basin and global reanalysis data,the climate characteristics,climate events,and meteorological disasters of the TGR in 2022 and 2023 were analyzed.For the TGR,the average annual temperature for 2022 and 2023 was 0.8℃ and 0.4℃ higher than normal,respectively,making them the two warmest years in the past decade.In 2022,the TGR experienced its warmest summer on record.The average air temperature was 2.4℃ higher than the average,and there were 24.8 days of above-average high temperature days during summer.Rainfall in the TGR varied significantly between 2022 and 2023.Annual rainfall was 18.4%below normal and drier than normal in most parts of the region.In contrast,the precipitation in 2023 was considerably higher than the long-term average,and above normal for almost the entire year.The average wind speed exhibited minimal variation between the two years.However,the number of foggy days and relative humidity increased in 2023 compared to 2022.In 2022–2023,the TGR mainly experienced meteorological disasters such as extreme high temperatures,regional heavy rain and flooding,overcast rain,and inverted spring chill.Analysis indicates that the abnormal western Pacific subtropical high and the abnormal persistence of the eastward-shifted South Asian high were the two important drivers of the durative enhancement of record-breaking high temperature in the summer of 2022.展开更多
As a major function of smart transportation in smart cities,vehicle model recognition plays an important role in intelligent transportation.Due to the difference among different vehicle models recognition datasets,the...As a major function of smart transportation in smart cities,vehicle model recognition plays an important role in intelligent transportation.Due to the difference among different vehicle models recognition datasets,the accuracy of network model training in one scene will be greatly reduced in another one.However,if you don’t have a lot of vehicle model datasets for the current scene,you cannot properly train a model.To address this problem,we study the problem of cold start of vehicle model recognition under cross-scenario.Under the condition of small amount of datasets,combined with the method of transfer learning,load the DAN(Deep Adaptation Networks)and JAN(Joint Adaptation Networks)domain adaptation modules into the convolutional neural network AlexNet and ResNet,and get four models:AlexNet-JAN,AlexNet-DAN,ResNet-JAN,and ResNet-DAN which can achieve a higher accuracy at the beginning.Through experiments,transfer the vehicle model recognition from the network image dataset(source domain)to the surveillance-nature dataset(target domain),both Top-1 and Top-5 accuracy have been improved by at least 20%.展开更多
Chirality hold broad applications in life sciences,quantum devices,and various other areas.Traditionally,molecular chirality can be characterized by using steady-state circular dichroism spectroscopy.However,the techn...Chirality hold broad applications in life sciences,quantum devices,and various other areas.Traditionally,molecular chirality can be characterized by using steady-state circular dichroism spectroscopy.However,the techniques that can characterize excited state chirality are progressively capturing the public interest as it can provide the dynamic information for chirality generation and transfer.In this review,we focus on the theoretical background and the developmental history of femtosecond time-resolved circular dichroism spectroscopy(TRCD)techniques around the world.Additionally,we provide examples to showcase the utility of these techniques in the analysis of the dynamical molecular chemical structures,the investigation of molecular chirality generation,and the detection of electron spin dynamics in semiconductor quantum dots.展开更多
[Objectives] To determine the nine phenolic components in the leaves of Crataegus pinnatifida Bge. [Methods] The reversedphase high-performance liquid chromatography( RP-HPLC) was applied. [Results] Nine phenolic comp...[Objectives] To determine the nine phenolic components in the leaves of Crataegus pinnatifida Bge. [Methods] The reversedphase high-performance liquid chromatography( RP-HPLC) was applied. [Results] Nine phenolic components showed a good linear relationship in the range of 2-500 μg/m L with r in the range of 0. 999 5-0. 999 9. The recovery rate of spiked samples ranged from 93. 7% to110. 2%,and the relative standard deviation was in the range of 0. 69%-4. 58%. The leaves of 29 cultivars of C. pinnatifida Bge. were measured,and the average content of the nine phenolic components was as follows: isoquercitrin,hyperoside,procyanidin C1,procyanidin D1,epicatechin,procyanidin B2,chlorogenic acid,eucomic acid,and vitexin 2 "-O-rhamnoside. The contents of flavonoids and phenolic acids were high,up to 15 mg/g D. W,and the content of procyanidins was up to 6 mg/g D. W. [Conclusions]This method is easy and accurate in determination of phenolic components in the leaves of C. pinnatifida Bge.展开更多
With the ability to generate forms with high efficiency and elegant geometry,topology optimization has been increasingly used in architectural and structural designs.However,the conventional topology optimization tech...With the ability to generate forms with high efficiency and elegant geometry,topology optimization has been increasingly used in architectural and structural designs.However,the conventional topology optimization techniques aim at achieving the structurally most efficient solution without any potential for architects or designers to control the design details.This paper introduces three strategies based on Bi-directional Evolutionary Structural Optimization(BESO)method to artificially pre-design the topological optimized structures.These strategies have been successfully applied in the computational morphogenesis of various structures for solving practical design problems.The results demonstrate that the developed methodology can provide the designer with structurally efficient and topologically different solutions according to their proposed designs with multi-filter radii,multi-volume fractions,and multi-weighting coefficients.This work establishes a general approach to integrating objective topology optimization methods with subjective human design preferences,which has great potential for practical applications in architecture and engineering industry.展开更多
Seawater electrolysis could address the water scarcity issue and realize the grid-scale production of carbon-neutral hydrogen,while facing the challenge of high energy consumption and chloride corrosion.Thermodynamica...Seawater electrolysis could address the water scarcity issue and realize the grid-scale production of carbon-neutral hydrogen,while facing the challenge of high energy consumption and chloride corrosion.Thermodynamically more favorable hydrazine oxidation reaction(HzOR)assisted water electrolysis is efficiency for energy-saving and chlorine-free hydrogen production.Herein,the MoNi alloys supported on MoO_(2) nanorods with enlarged hollow diameter on Ni foam(MoNi@NF)are synthesized,which is constructed by limiting the outward diffusion of Ni via annealing and thermal reduction of NiMoO_(4) nanorods.When coupling HzOR and hydrogen evolution reaction(HER)by employing MoNi@NF as both anode and cathode in two-electrode seawater system,a low cell voltage of 0.54 V is required to achieve 1,000 mA·cm^(−2) and with long-term durability for 100 h to keep above 100 mA·cm^(−2) and nearly 100%Faradaic efficiency.It can save 2.94 W·h to generate per liter H_(2) relative to alkaline seawater electrolysis with 37%lower energy equivalent input.展开更多
In Northeast China,Goubao pickle is a popular food fermented from the roots of Platycodon grandiflorum as the main material,offering a unique flavor and rich nutritional value.Platycosides in roots of P.grandiflorum m...In Northeast China,Goubao pickle is a popular food fermented from the roots of Platycodon grandiflorum as the main material,offering a unique flavor and rich nutritional value.Platycosides in roots of P.grandiflorum may play a crucial role in determining the quality of Goubao pickle through microorganism fermentation.However,biotransfermation of platycosides has not been reviewed during fermentation.In this study,we reviewed platycosides in chemical diversity,metabolic processes in vivo,biotransformation of platycosides in vitro,and pharmacological effects.Finally,we also discussed how to improve the bioactive secondary platycosides we desire by regulating enzymes from microorganisms in the future.展开更多
Strong light-matter interactions in two-dimensional transition metal dichalcogenides(TMDCs)with robust spin-valley degrees of freedom open up the prospect of valleytronic devices.A thorough understanding on the dynami...Strong light-matter interactions in two-dimensional transition metal dichalcogenides(TMDCs)with robust spin-valley degrees of freedom open up the prospect of valleytronic devices.A thorough understanding on the dynamics of the valley polarizations in the strong coupling regime is urgently required.Here,multiple polarized TMDCs-SPPs hybrid systems were constructed by combining monolayer WS_(2)flakes to linear,circular,and spiral Ag gratings,resulting in linear and circular polarized modula-tion on the coherent hybrid states,respectively.Particularly,valley polaritons can be tailored asymmetrically by chiral strong coupling regime.Furthermore,the dynamics of the polarized polaritons were directly analyzed by transient absorption(TA)measure-ment.Both of the linear and circular polarization difference in the TA spectra can be retained for a remarkable long time,leading to a polarized PL even at room tempera-ture.More importantly,in the chiral strong coupled WS_(2)-spiral Ag grating devices,the mechanism of the asymmetrical valley-polarized PL(p_(σ+)=14.9%and p_(σ-)=10.8%)is proved by the opposite valley polarization dynamics in the circularly polarized TA spectra.The multiple polarization modulation in monolayer TMDCs-SPPs strong coupling devices could provide a viable route toward multiple polarization polaritonic devices.展开更多
文摘The digitisation of musical manuscripts has transformed them from static heritage assets into dynamic data capital.This study explores how digitisation enhances the cultural value of musical manuscripts in low-resource contexts,focusing on Kyrgyz instrumental traditions(küü).Grounded in the SCP-R(Structure,Culture,Performance,and Resources)model,we analyse digitisation's impact through structural,cultural,performance,and resource dimensions.We propose a three-stage"embed–reconstruct–transform"framework,leveraging 12,400 folios and 2,300 hours of audio from the Kyrgyz National Conservatory.A Kyrgyz-tuned Transformer(MusicKG-T)trained with nomadic-path contrastive learning(CMCL-Kyrgyz)demonstrates that digitisation improves accessibility and usability,significantly increasing cultural and economic value.Findings offer a reproducible workflow for Silk-Road archives and highlight implications for music education and cultural policy.Future research should validate applicability to vocal traditions and other regions.
基金supported by the Innovation and Development Special Project of the China Meteorological Administration[grant number CXFZ2024J071]the National Key Research and Development Program of China[grant number 2023YFC3206001].
文摘The Three Gorges Region(TGR)of the Yangtze River basin exhibited warm and dry climatic characteristics in 2024.The annual mean temperature in the TGR was 18.6℃,which was 1.2℃above normal and marked the highest level since 1961.All four seasons were warmer than normal,with spring and autumn both recording their highest temperatures since 1961.Additionally,the TGR recorded 57.2 high-temperature days in 2024,reaching a historic high since 1961 and exceeding the previous record set in 2022 by 2.4 days.Annual rainfall was 11.2%below normal,with spring,summer,and autumn all being drier than normal.However,the number of heavy rain days was slightly higher than normal.The annual mean wind speed in the TGR ranked as the second-highest since 1961,only slightly lower than in 2022.The annual mean relative humidity was below normal and the number of fog days across large areas of the TGR decreased compared to 2023.In 2024,the TGR experienced extreme high-temperature events characterized by exceptional intensity and prolonged duration,accompanied by generally severe meteorological drought conditions.During the year,the TGR also experienced frequent and intense cooling events,an early onset of heavy rainfall(including severe convective weather),and exceptionally extreme rainstorm events.
文摘The year 2024 witnessed remarkable climatic anomalies across China,characterized by pronounced warm and wet conditions.The annual mean temperature soared to a record high since 1951,with seasonal temperatures in spring,summer,and autumn all exceeding historical extremes.Meanwhile,the annual precipitation ranked as the fourth highest on record,with all four seasons experiencing above-average rainfall.Notably,the Yangtze River Basin and Jiangnan region encountered their most intense precipitation event since 1961.Extreme weather events were particularly striking:An unusually early and severe heatwave swept through central and eastern China,becoming the second most intense high-temperature event in recorded history.Autumn typhoon activity also displayed exceptional intensity,with Typhoon Yagi triggering significant impacts in Hainan,Guangdong,and Guangxi.Although drought conditions were generally mild overall,notable seasonal and regional disparities emerged,especially in the winter–spring droughts affecting southwestern China.Conversely,cold outbreaks occurred more frequently than usual,and convective weather events exhibited heightened activity.Moreover,dust storm activity remained relatively limited.
基金supported by the National Key R&D Program of China[grant numbers 2017YFD0300201,2017YFA0605004,and 2017YFC1502402]funds of comprehensive monitoring of the Three Gorges Project,which was financed by the Ministry of Water Resources of China。
文摘In 2020,the average air temperature in the Three Gorges Region(TGR)of the Yangtze River basin was 17.2℃,which was close to normal,there were exceptionally fewer days than normal with high temperatures,and the high-temperature events mainly occurred in August.Meanwhile,the average precipitation was 1530.8 mm,which was a remarkable 29%more than usual,and the second-highest since 1961.The precipitation was obviously above-normal in summer,and the precipitation in both June and July was the second-highest of the same period in history.The average number of rainstorm days was higher than normal,and the second-highest since 1961.The average wind speed in the TGR was apparently higher than normal;the average relative humidity was slightly higher than normal;and there were no instances of acid rain,with the rain acidity showing a significant weakening trend over the previous 15 years.In the summer of 2020,the TGR experienced heavy rainstorms and flood disasters.Analysis shows that the frequent southward movement of cold air and abundant warm water vapor from the southwest were the direct causes of the abnormally high precipitation in the TGR from June to July.After the spring of 2020,the continuously high sea surface temperature in the Indian Ocean led to a continuously strong western Pacific subtropical high and its average location being situated more to the south than normal,which might have been an important cause for the abnormal climate conditions in the Yangtze River basin from June to July.
基金This study was supported by the National Key R&D Program of China[grant numbers 2017YFC1502402,2017YFD0300201,and 2017YFA0605004]the funds of comprehensive monitoring of the Three Gorges Project,which was financed by the Ministry of Water Resources of China.
文摘This report provides a broad overview of the climate and the major weather and climate events over the Three Gorges Region of the Yangtze River(TGR)in 2019.The year 2019,a 0.3℃ warmer year than normal,had a colder winter and warmer spring,summer,and autumn.Annual precipitation in 2019 was 13%less than normal.Below average normal rainfall amounts were received in all four seasons,with 28%and 16%less-than-normal in winter and summer,respectively.The annual mean wind speed in the TGR was higher than normal,and relative humidity was near normal for all four seasons.The intensity of acid rain in 2019 was the weakest since 1999.The major climate events and meteorological disasters in the TGR in 2019 included heat waves,drought,and rainstorms.Heat waves occurred frequently and persisted for long durations.Summer and autumn drought occurred in central and eastern regions of the TGR.The autumn rains of West China occurred earlier this year,which brought much more rainfall than normal in central and western regions of the TGR.
基金jointly supported by the funds of the Strategic Cooperation Agreement Project between the China Meteorological Administration and the Three Gorges Corporation[Grant No.0704182]the Comprehensive Monitoring Program for Operational Safety of the Three Gorges Project[Grant No.SK2021015]financed by the Ministry of Water Resources of China.
文摘Based on daily observation data in the Three Gorges Region(TGR)of the Yangtze River Basin and global reanalysis data,the authors analyzed the climate characteristics and associated temporal variations in the main meteorological factors in 2021,as well as the year’s climatic events and meteorological disasters.The 2021 average temperature was 0.2℃above the 1991-2020 average and the 13 th-warmest year since 1961.Seasonally,winter and autumn were both warmer than usual.The annual mean precipitation was 12.8%above normal,and most regions experienced abundant rainfall throughout the year.The seasonal variation in precipitation was significant and the TGR had a wetter-than-normal spring and summer.The number of rainstorm days was higher than normal;the wind speed was above normal;and the relative humidity was higher than normal.In terms of rain acidity,2021 was tied with 2020 as the lowest since 1999.From mid-September to early October 2021,the TGR experienced exceptional high-temperature weather,which was driven by abnormal activity of mid-and high-latitude atmospheric circulation over the Eurasian continent and the western Pacific subtropical high(WPSH).In addition,a strong blocking high over the Ural Mountains accompanied by intense mid-latitude westerly winds prevented cyclonic disturbances from extending to the subtropical region.As a result,under the combined effect of the weaker-than-normal cold-air activities and the anomalous WPSH,the TGR experienced extreme high-temperature weather during early autumn 2021.
文摘Highly efficient and stable bifunctional electrocatalysts that can be used for large-current-density electrolysis of alkaline seawater are highly desirable for carbon-neutral economies,but their facile and controllable synthesis remains a challenge.Here,self-assembled ultralow Ru,Ni-doped Fe_(2)O_(3) with a lily shaped morphology was synthesized on iron foam(RuNi-Fe_(2)O_(3)/IF)via a facile one-step hydrothermal process,in which the intact lily shaped RuNi-Fe_(2)O_(3)/IF was obtained by adjusting the ratio of Ru/Ni.Benefitting from the Ru/Ni chemical substitution,the as-synthesized RuNi-Fe_(2)O_(3)/IF can act as free-standing dual-function electrodes that are applied to electrocatalysis for the hydrogen evolution(HER)and oxygen evolution reactions(OER)in 1.0 mol L^(-1) KOH,requiring an overpotential of 75.0 mV to drive 100 mA cm^(-2) for HER and 329.0 mV for OER.Moreover,the overall water splitting catalyzed by RuNi-Fe_(2)O_(3)/IF only demands ultralow cell voltages of 1.66 and 1.73 V to drive 100 mA cm^(-2) in 1.0 mol L^(-1) KOH and 1.0 mol L^(-1) KOH seawater electrolytes,respectively.The electrodes show remarkable long-term durability,maintaining current densities exceeding 100 mA cm^(-2) for more than 100 h and thus outperforming the two-electrode system composed of noble catalysts.This work provides an efficient,economical method to synthesize self-standing bifunctional electrodes for large-current-density alkaline seawater electrolysis,which is of significant importance for ecological protection and energy exploitation.
基金supported by the National Key Research and Development Program of China[grant number 2023YFC3206001]the Three Gorges Project Comprehensive Monitoring Program for Operational Safety[grant number SK2023019]which funded by the Ministry of Water Resources of China.
文摘Based on daily observation data of the Three Gorges Region(TGR)of the Yangtze River basin and global reanalysis data,the climate characteristics,climate events,and meteorological disasters of the TGR in 2022 and 2023 were analyzed.For the TGR,the average annual temperature for 2022 and 2023 was 0.8℃ and 0.4℃ higher than normal,respectively,making them the two warmest years in the past decade.In 2022,the TGR experienced its warmest summer on record.The average air temperature was 2.4℃ higher than the average,and there were 24.8 days of above-average high temperature days during summer.Rainfall in the TGR varied significantly between 2022 and 2023.Annual rainfall was 18.4%below normal and drier than normal in most parts of the region.In contrast,the precipitation in 2023 was considerably higher than the long-term average,and above normal for almost the entire year.The average wind speed exhibited minimal variation between the two years.However,the number of foggy days and relative humidity increased in 2023 compared to 2022.In 2022–2023,the TGR mainly experienced meteorological disasters such as extreme high temperatures,regional heavy rain and flooding,overcast rain,and inverted spring chill.Analysis indicates that the abnormal western Pacific subtropical high and the abnormal persistence of the eastward-shifted South Asian high were the two important drivers of the durative enhancement of record-breaking high temperature in the summer of 2022.
基金This work was supported by CETC Joint Research Program under Grant 6141B08020101,6141B08080101National Key R&D Program of China under Grant 2018ZX09201014the National Natural Science Foundation of China under Grant 61002011.
文摘As a major function of smart transportation in smart cities,vehicle model recognition plays an important role in intelligent transportation.Due to the difference among different vehicle models recognition datasets,the accuracy of network model training in one scene will be greatly reduced in another one.However,if you don’t have a lot of vehicle model datasets for the current scene,you cannot properly train a model.To address this problem,we study the problem of cold start of vehicle model recognition under cross-scenario.Under the condition of small amount of datasets,combined with the method of transfer learning,load the DAN(Deep Adaptation Networks)and JAN(Joint Adaptation Networks)domain adaptation modules into the convolutional neural network AlexNet and ResNet,and get four models:AlexNet-JAN,AlexNet-DAN,ResNet-JAN,and ResNet-DAN which can achieve a higher accuracy at the beginning.Through experiments,transfer the vehicle model recognition from the network image dataset(source domain)to the surveillance-nature dataset(target domain),both Top-1 and Top-5 accuracy have been improved by at least 20%.
基金funded by the National Natural Science Foundation of China(No.92156024and No.92356307 to Jinquan Chen)Menghui Jia thanks the Materials Characterization Center and the Office of Laboratory and Equipment of East China Normal University for funding support(ECNUETR2023-13).
文摘Chirality hold broad applications in life sciences,quantum devices,and various other areas.Traditionally,molecular chirality can be characterized by using steady-state circular dichroism spectroscopy.However,the techniques that can characterize excited state chirality are progressively capturing the public interest as it can provide the dynamic information for chirality generation and transfer.In this review,we focus on the theoretical background and the developmental history of femtosecond time-resolved circular dichroism spectroscopy(TRCD)techniques around the world.Additionally,we provide examples to showcase the utility of these techniques in the analysis of the dynamical molecular chemical structures,the investigation of molecular chirality generation,and the detection of electron spin dynamics in semiconductor quantum dots.
基金Supported by Project of Natural Science Foundation of Hebei Province(C2015204187)
文摘[Objectives] To determine the nine phenolic components in the leaves of Crataegus pinnatifida Bge. [Methods] The reversedphase high-performance liquid chromatography( RP-HPLC) was applied. [Results] Nine phenolic components showed a good linear relationship in the range of 2-500 μg/m L with r in the range of 0. 999 5-0. 999 9. The recovery rate of spiked samples ranged from 93. 7% to110. 2%,and the relative standard deviation was in the range of 0. 69%-4. 58%. The leaves of 29 cultivars of C. pinnatifida Bge. were measured,and the average content of the nine phenolic components was as follows: isoquercitrin,hyperoside,procyanidin C1,procyanidin D1,epicatechin,procyanidin B2,chlorogenic acid,eucomic acid,and vitexin 2 "-O-rhamnoside. The contents of flavonoids and phenolic acids were high,up to 15 mg/g D. W,and the content of procyanidins was up to 6 mg/g D. W. [Conclusions]This method is easy and accurate in determination of phenolic components in the leaves of C. pinnatifida Bge.
文摘With the ability to generate forms with high efficiency and elegant geometry,topology optimization has been increasingly used in architectural and structural designs.However,the conventional topology optimization techniques aim at achieving the structurally most efficient solution without any potential for architects or designers to control the design details.This paper introduces three strategies based on Bi-directional Evolutionary Structural Optimization(BESO)method to artificially pre-design the topological optimized structures.These strategies have been successfully applied in the computational morphogenesis of various structures for solving practical design problems.The results demonstrate that the developed methodology can provide the designer with structurally efficient and topologically different solutions according to their proposed designs with multi-filter radii,multi-volume fractions,and multi-weighting coefficients.This work establishes a general approach to integrating objective topology optimization methods with subjective human design preferences,which has great potential for practical applications in architecture and engineering industry.
基金supported by the National Natural Science Foundation of China(Nos.51772162 and 52072197)the Outstanding Youth Foundation of Shandong Province,China(No.ZR2019JQ14)+3 种基金the Youth Innovation and Technology Foundation of Shandong Higher Education Institutions,China(No.2019KJC004)the Major Scientific and Technological Innovation Project(No.2019JZZY020405)the Major Basic Research Program of Natural Science Foundation of Shandong Province(No.ZR2020ZD09)the Taishan Scholar Young Talent Program(No.tsqn201909114).
文摘Seawater electrolysis could address the water scarcity issue and realize the grid-scale production of carbon-neutral hydrogen,while facing the challenge of high energy consumption and chloride corrosion.Thermodynamically more favorable hydrazine oxidation reaction(HzOR)assisted water electrolysis is efficiency for energy-saving and chlorine-free hydrogen production.Herein,the MoNi alloys supported on MoO_(2) nanorods with enlarged hollow diameter on Ni foam(MoNi@NF)are synthesized,which is constructed by limiting the outward diffusion of Ni via annealing and thermal reduction of NiMoO_(4) nanorods.When coupling HzOR and hydrogen evolution reaction(HER)by employing MoNi@NF as both anode and cathode in two-electrode seawater system,a low cell voltage of 0.54 V is required to achieve 1,000 mA·cm^(−2) and with long-term durability for 100 h to keep above 100 mA·cm^(−2) and nearly 100%Faradaic efficiency.It can save 2.94 W·h to generate per liter H_(2) relative to alkaline seawater electrolysis with 37%lower energy equivalent input.
基金supported by the National Natural Science Foundation of China(No.U20A20400)the Scientific Research Foundation of Heilongjiang Provincial Scientific Research Institutes(No.CZKYF2021A002)Young and middle-aged graduate tutor training program of Shenyang Agricultural University(No.2022-ZZDS-09).
文摘In Northeast China,Goubao pickle is a popular food fermented from the roots of Platycodon grandiflorum as the main material,offering a unique flavor and rich nutritional value.Platycosides in roots of P.grandiflorum may play a crucial role in determining the quality of Goubao pickle through microorganism fermentation.However,biotransfermation of platycosides has not been reviewed during fermentation.In this study,we reviewed platycosides in chemical diversity,metabolic processes in vivo,biotransformation of platycosides in vitro,and pharmacological effects.Finally,we also discussed how to improve the bioactive secondary platycosides we desire by regulating enzymes from microorganisms in the future.
基金supported by the National Key Research and Development Program of China and the National Natural Science Foundation of China(NSFC)under Grants 21903035,22073037,21773087,12074141,61960206003Jilin Provincial Science and Technology Development Project(20210509038RQ).
文摘Strong light-matter interactions in two-dimensional transition metal dichalcogenides(TMDCs)with robust spin-valley degrees of freedom open up the prospect of valleytronic devices.A thorough understanding on the dynamics of the valley polarizations in the strong coupling regime is urgently required.Here,multiple polarized TMDCs-SPPs hybrid systems were constructed by combining monolayer WS_(2)flakes to linear,circular,and spiral Ag gratings,resulting in linear and circular polarized modula-tion on the coherent hybrid states,respectively.Particularly,valley polaritons can be tailored asymmetrically by chiral strong coupling regime.Furthermore,the dynamics of the polarized polaritons were directly analyzed by transient absorption(TA)measure-ment.Both of the linear and circular polarization difference in the TA spectra can be retained for a remarkable long time,leading to a polarized PL even at room tempera-ture.More importantly,in the chiral strong coupled WS_(2)-spiral Ag grating devices,the mechanism of the asymmetrical valley-polarized PL(p_(σ+)=14.9%and p_(σ-)=10.8%)is proved by the opposite valley polarization dynamics in the circularly polarized TA spectra.The multiple polarization modulation in monolayer TMDCs-SPPs strong coupling devices could provide a viable route toward multiple polarization polaritonic devices.
