The Northeast China cold vortex(NCCV)during late summer(from July to August)is identified and classified into three types in terms of its movement path using machine learning.The relationships of the three types of NC...The Northeast China cold vortex(NCCV)during late summer(from July to August)is identified and classified into three types in terms of its movement path using machine learning.The relationships of the three types of NCCV intensity with atmospheric circulations in late summer,the sea surface temperature(SST),and Arctic sea ice concentration(SIC)in the preceding months,are analyzed.The sensitivity tests by the Community Atmosphere Model version 5.3(CAM5.3)are used to verify the statistical results.The results show that the coordination pattern of East Asia-Pacific(EAP)and Lake Baikal high pressure forced by SST anomalies in the North Indian Ocean dipole mode(NIOD)during the preceding April and SIC anomalies in the Nansen Basin during the preceding June results in an intensity anomaly for the first type of NCCV.While the pattern of high pressure over the Urals and Okhotsk Sea and low pressure over Lake Baikal during late summer-which is forced by SST anomalies in the South Indian Ocean dipole mode(SIOD)in the preceding June and SIC anomalies in the Barents Sea in the preceding April-causes the intensity anomaly of the second type.The third type is atypical and is not analyzed in detail.Sensitivity tests,jointly forced by the SST and SIC in the preceding period,can well reproduce the observations.In contrast,the results forced separately by the SST and SIC are poor,indicating that the NCCV during late summer is likely influenced by the coordinated effects of both SST and SIC in the preceding months.展开更多
The classification of the Northeast China Cold Vortex(NCCV)activity paths is an important way to analyze its characteristics in detail.Based on the daily precipitation data of the northeastern China(NEC)region,and the...The classification of the Northeast China Cold Vortex(NCCV)activity paths is an important way to analyze its characteristics in detail.Based on the daily precipitation data of the northeastern China(NEC)region,and the atmospheric circulation field and temperature field data of ERA-Interim for every six hours,the NCCV processes during the early summer(June)seasons from 1979 to 2018 were objectively identified.Then,the NCCV processes were classified using a machine learning method(k-means)according to the characteristic parameters of the activity path information.The rationality of the classification results was verified from two aspects,as follows:(1)the atmospheric circulation configuration of the NCCV on various paths;and(2)its influences on the climate conditions in the NEC.The obtained results showed that the activity paths of the NCCV could be divided into four types according to such characteristics as the generation origin,movement direction,and movement velocity of the NCCV.These included the generation-eastward movement type in the east of the Mongolia Plateau(eastward movement type or type A);generation-southeast longdistance movement type in the upstream of the Lena River(southeast long-distance movement type or type B);generationeastward less-movement type near Lake Baikal(eastward less-movement type or type C);and the generation-southward less-movement type in eastern Siberia(southward less-movement type or type D).There were obvious differences observed in the atmospheric circulation configuration and the climate impact of the NCCV on the four above-mentioned types of paths,which indicated that the classification results were reasonable.展开更多
Knowledge of sediment variation processes is essential to understand the evolution mechanism of beach morphology changes.Thus,a field measurement was conducted at the Heisha Beach,located on the west coast of the Zhuj...Knowledge of sediment variation processes is essential to understand the evolution mechanism of beach morphology changes.Thus,a field measurement was conducted at the Heisha Beach,located on the west coast of the Zhujiang River(Pearl River)Estuary,to investigate the short-term variation in suspended sediment concentrations(SSCs)and the relationship between the SSC and turbulent kinetic energy,bottom shear stress(BSS),and relative wave height.Based on extreme event analysis results,extreme events have a greater influence on turbulent kinetic energy than SSC.Although a portion of the turbulent kinetic energy dissipates directly into the water column,it plays an important role in suspended sediment motion.Most of the time,the wave-current interaction is strong enough to drive sediment incipience and resuspension.When combined,the wave-current interaction and wave-induced BSSs have a greater influence on suspended sediment transport and SSC variation than current-induced BSS alone.The relative wave height also has a strong correlation with SSC,indicating that the combined effect of water depth and wave height significantly impacts SSC variation.Water depth is mainly controlled by the tide on the beaches;thus,the effects of tides and waves should be conjunctively considered when analyzing the factors influencing SSC.展开更多
The enzyme-mimicking catalytic activity of single-atom nanozymes has been widely used in tumor treatment.However,research on alleviating metabolic diseases,such as hyperglycemia,has not been reported.Herein,we found t...The enzyme-mimicking catalytic activity of single-atom nanozymes has been widely used in tumor treatment.However,research on alleviating metabolic diseases,such as hyperglycemia,has not been reported.Herein,we found that the single-atom Ce-N_(4)-C-(OH)_(2)(SACe-N_(4)-C-(OH)_(2))nanozyme promoted glucose absorption in lysosomes,resulting in increased reactive oxygen species production in HepG2 cells.Furthermore,the SACe-N_(4)-C-(OH)_(2)nanozyme initiated a cascade reaction involving superoxide dismutase-,oxidase-,catalase-,and peroxidase-like activity to overcome the limitations associated with the substrate and produce•OH,thus improving glucose intolerance and insulin resistance by increasing the phosphorylation of protein kinase B and glycogen synthase kinase 3β,and the expression of glycogen synthase,promoting glycogen synthesis to improve glucose intolerance and insulin resistance in high-fat diet-induced hyperglycemic mice.Altogether,these results demonstrated that the novel nanozyme SACeN_(4)-C-(OH)_(2)alleviated the effects of hyperglycemia without evident toxicity,demonstrating its excellent clinical application potential.展开更多
Using the hindcasts provided by the Ensemble-Based Predictions of Climate Changes and Their Impacts(ENSEMBLES) project for the period of 1980–2005, the forecast capability of spring climate in China is assessed mainl...Using the hindcasts provided by the Ensemble-Based Predictions of Climate Changes and Their Impacts(ENSEMBLES) project for the period of 1980–2005, the forecast capability of spring climate in China is assessed mainly from the aspects of precipitation, 2-m air temperature, and atmospheric circulations. The ENSEMBELS can reproduce the climatology and dominant empirical orthogonal function(EOF) modes of precipitation and 2-m air temperature, with some differences arising from different initialization months. The multi-model ensemble(MME) forecast of interannual variability is of good performance in some regions such as eastern China with February initialization.The spatial patterns of the MME interannual and inter-member spreads for precipitation and 2-m air temperature are consistent with those of the observed interannual spread, indicating that internal dynamic processes have major impacts on the interannual anomaly of spring climate in China. We have identified two coupled modes between intermember anomalies of the 850-hPa vorticity in spring and sea surface temperature(SST) both in spring and at a lead of 2 months, of which the first mode shows a significant impact on the spring climate in China, with an anomalous anticyclone located over Northwest Pacific and positive precipitation and southwesterly anomalies in eastern China.Our results also suggest that the SST at a lead of two months may be a predictor for the spring climate in eastern China. A better representation of the ocean–atmosphere interaction over the tropical Pacific, Northwest Pacific, and Indian Ocean can improve the forecast skill of the spring climate in eastern China.展开更多
With the rapid development of white LEDs,the research of new and efficient white light emitting materials has attracted increasing attention.Zero dimensional(0D)organic–inorganic hybrid metal halide perovskites with ...With the rapid development of white LEDs,the research of new and efficient white light emitting materials has attracted increasing attention.Zero dimensional(0D)organic–inorganic hybrid metal halide perovskites with superior luminescent property are promising candidates for LED application,due to their abundant and tailorable structure.Herein,[(CH_(3))_(3)S]_(2)SnCl_(6)・H_(2)O is synthesized as a host for dopant ions Bi^(3+)and Sb^(3+).The Sb^(3+)doped,or Bi^(3+)/Sb^(3+)co-doped,[(CH_(3))3S]_(2)SnCl_(6)・H_(2)O has a tunable optical emission spectrum by means of varying dopant ratio and excitation wavelength.As a result,we can achieve single-phase materials suitable for emission ranging from cold white light to warm white light.The intrinsic mechanism is examined in this work,to clarify the dopant effect on the optical properties.The high stability of title crystalline material,against water,oxygen and heat,makes it promising for further application.展开更多
基金jointly supported by the National Natural Science Foundation of China (Grant No. 42005037)Special Project of Innovative Development, CMA (CXFZ2021J022, CXFZ2022J008, and CXFZ2021J028)+1 种基金Liaoning Provincial Natural Science Foundation Project (Ph.D. Start-up Research Fund 2019-BS214)Research Project of the Institute of Atmospheric Environment, CMA (2021SYIAEKFMS08, 2020SYIAE08 and 2021SYIAEKFMS09)
文摘The Northeast China cold vortex(NCCV)during late summer(from July to August)is identified and classified into three types in terms of its movement path using machine learning.The relationships of the three types of NCCV intensity with atmospheric circulations in late summer,the sea surface temperature(SST),and Arctic sea ice concentration(SIC)in the preceding months,are analyzed.The sensitivity tests by the Community Atmosphere Model version 5.3(CAM5.3)are used to verify the statistical results.The results show that the coordination pattern of East Asia-Pacific(EAP)and Lake Baikal high pressure forced by SST anomalies in the North Indian Ocean dipole mode(NIOD)during the preceding April and SIC anomalies in the Nansen Basin during the preceding June results in an intensity anomaly for the first type of NCCV.While the pattern of high pressure over the Urals and Okhotsk Sea and low pressure over Lake Baikal during late summer-which is forced by SST anomalies in the South Indian Ocean dipole mode(SIOD)in the preceding June and SIC anomalies in the Barents Sea in the preceding April-causes the intensity anomaly of the second type.The third type is atypical and is not analyzed in detail.Sensitivity tests,jointly forced by the SST and SIC in the preceding period,can well reproduce the observations.In contrast,the results forced separately by the SST and SIC are poor,indicating that the NCCV during late summer is likely influenced by the coordinated effects of both SST and SIC in the preceding months.
基金This research was jointly supported by the National Natural Science Foundation of China(Grant No.42005037)the Liaoning Provincial Natural Science Foundation Project(PhD Start-up Research Fund 2019-BS-214),the Special Scientific Research Project for the Forecaster(Grant No.CMAYBY2018-018)+2 种基金a Key Technical Project of Liaoning Meteorological Bureau(Grant No.LNGJ201903)the National Key Research and Development Project(Grant No.2018YFC1505601)the Open Foundation Project of the Institute of Atmospheric Environment,China Meteorological Administration(Grant Nos.2020SYIAE08 and 2020SYIAEZD5).
文摘The classification of the Northeast China Cold Vortex(NCCV)activity paths is an important way to analyze its characteristics in detail.Based on the daily precipitation data of the northeastern China(NEC)region,and the atmospheric circulation field and temperature field data of ERA-Interim for every six hours,the NCCV processes during the early summer(June)seasons from 1979 to 2018 were objectively identified.Then,the NCCV processes were classified using a machine learning method(k-means)according to the characteristic parameters of the activity path information.The rationality of the classification results was verified from two aspects,as follows:(1)the atmospheric circulation configuration of the NCCV on various paths;and(2)its influences on the climate conditions in the NEC.The obtained results showed that the activity paths of the NCCV could be divided into four types according to such characteristics as the generation origin,movement direction,and movement velocity of the NCCV.These included the generation-eastward movement type in the east of the Mongolia Plateau(eastward movement type or type A);generation-southeast longdistance movement type in the upstream of the Lena River(southeast long-distance movement type or type B);generationeastward less-movement type near Lake Baikal(eastward less-movement type or type C);and the generation-southward less-movement type in eastern Siberia(southward less-movement type or type D).There were obvious differences observed in the atmospheric circulation configuration and the climate impact of the NCCV on the four above-mentioned types of paths,which indicated that the classification results were reasonable.
基金The National Key Research and Development Program of China under contract No.2016YFC0402603the Guangdong Provincial Department of Natural Resources Project under contract No.42090038the Guangdong Provincial Department of Ocean and Fisheries Project under contract No.42090033.
文摘Knowledge of sediment variation processes is essential to understand the evolution mechanism of beach morphology changes.Thus,a field measurement was conducted at the Heisha Beach,located on the west coast of the Zhujiang River(Pearl River)Estuary,to investigate the short-term variation in suspended sediment concentrations(SSCs)and the relationship between the SSC and turbulent kinetic energy,bottom shear stress(BSS),and relative wave height.Based on extreme event analysis results,extreme events have a greater influence on turbulent kinetic energy than SSC.Although a portion of the turbulent kinetic energy dissipates directly into the water column,it plays an important role in suspended sediment motion.Most of the time,the wave-current interaction is strong enough to drive sediment incipience and resuspension.When combined,the wave-current interaction and wave-induced BSSs have a greater influence on suspended sediment transport and SSC variation than current-induced BSS alone.The relative wave height also has a strong correlation with SSC,indicating that the combined effect of water depth and wave height significantly impacts SSC variation.Water depth is mainly controlled by the tide on the beaches;thus,the effects of tides and waves should be conjunctively considered when analyzing the factors influencing SSC.
基金This work was supported by the Natural Science Foundation of China(Grant No.32001787)the 2115 Talent Development Program of China Agricultural University。
文摘The enzyme-mimicking catalytic activity of single-atom nanozymes has been widely used in tumor treatment.However,research on alleviating metabolic diseases,such as hyperglycemia,has not been reported.Herein,we found that the single-atom Ce-N_(4)-C-(OH)_(2)(SACe-N_(4)-C-(OH)_(2))nanozyme promoted glucose absorption in lysosomes,resulting in increased reactive oxygen species production in HepG2 cells.Furthermore,the SACe-N_(4)-C-(OH)_(2)nanozyme initiated a cascade reaction involving superoxide dismutase-,oxidase-,catalase-,and peroxidase-like activity to overcome the limitations associated with the substrate and produce•OH,thus improving glucose intolerance and insulin resistance by increasing the phosphorylation of protein kinase B and glycogen synthase kinase 3β,and the expression of glycogen synthase,promoting glycogen synthesis to improve glucose intolerance and insulin resistance in high-fat diet-induced hyperglycemic mice.Altogether,these results demonstrated that the novel nanozyme SACeN_(4)-C-(OH)_(2)alleviated the effects of hyperglycemia without evident toxicity,demonstrating its excellent clinical application potential.
基金Supported by the National Natural Science Foundation of China(41575077,41490643,and 41805051)National Key Research and Development Program of China(2017YFA0604102)+1 种基金Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)Startup Found for Introduced Talents of Nanjing University of Information Science&Technology(2017r057)
文摘Using the hindcasts provided by the Ensemble-Based Predictions of Climate Changes and Their Impacts(ENSEMBLES) project for the period of 1980–2005, the forecast capability of spring climate in China is assessed mainly from the aspects of precipitation, 2-m air temperature, and atmospheric circulations. The ENSEMBELS can reproduce the climatology and dominant empirical orthogonal function(EOF) modes of precipitation and 2-m air temperature, with some differences arising from different initialization months. The multi-model ensemble(MME) forecast of interannual variability is of good performance in some regions such as eastern China with February initialization.The spatial patterns of the MME interannual and inter-member spreads for precipitation and 2-m air temperature are consistent with those of the observed interannual spread, indicating that internal dynamic processes have major impacts on the interannual anomaly of spring climate in China. We have identified two coupled modes between intermember anomalies of the 850-hPa vorticity in spring and sea surface temperature(SST) both in spring and at a lead of 2 months, of which the first mode shows a significant impact on the spring climate in China, with an anomalous anticyclone located over Northwest Pacific and positive precipitation and southwesterly anomalies in eastern China.Our results also suggest that the SST at a lead of two months may be a predictor for the spring climate in eastern China. A better representation of the ocean–atmosphere interaction over the tropical Pacific, Northwest Pacific, and Indian Ocean can improve the forecast skill of the spring climate in eastern China.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.22373014 and 22371043)the Natural Science Foundation of Fujian Province(No.2022J06019)the Open Project Program of Wuhan National Laboratory for Optoelectronics(No.2020WNLOKF009).
文摘With the rapid development of white LEDs,the research of new and efficient white light emitting materials has attracted increasing attention.Zero dimensional(0D)organic–inorganic hybrid metal halide perovskites with superior luminescent property are promising candidates for LED application,due to their abundant and tailorable structure.Herein,[(CH_(3))_(3)S]_(2)SnCl_(6)・H_(2)O is synthesized as a host for dopant ions Bi^(3+)and Sb^(3+).The Sb^(3+)doped,or Bi^(3+)/Sb^(3+)co-doped,[(CH_(3))3S]_(2)SnCl_(6)・H_(2)O has a tunable optical emission spectrum by means of varying dopant ratio and excitation wavelength.As a result,we can achieve single-phase materials suitable for emission ranging from cold white light to warm white light.The intrinsic mechanism is examined in this work,to clarify the dopant effect on the optical properties.The high stability of title crystalline material,against water,oxygen and heat,makes it promising for further application.
