To ensure the safety of power energy transmission channel and mitigate the harm caused by galloping of iced transmission lines,the axial time-delay velocity feedback strategy is adopted to suppress the galloping.The p...To ensure the safety of power energy transmission channel and mitigate the harm caused by galloping of iced transmission lines,the axial time-delay velocity feedback strategy is adopted to suppress the galloping.The par-tial differential equation of galloping with axial time-delay velocity feedback strategy is established based on the variational principle for Hamiltonian.Then,the partial differential equation of galloping is transformed into or-dinary differential equation based on normalization and the Galerkin method.The primary amplitude-frequency response equation,the first-order steady-state approximate solution,and the harmonic amplitude-frequency re-sponse equation are derived by the multiscale method.The impact of different parameters such as time-delay value,control coefficient,and amplitude of external excitation on the galloping response are analyzed.The am-plitude under the primary resonance exhibits periodicity as time-delay value varies.The amplitude diminishes with increased control coefficient and increases with external excitation.Comprehensive consideration of vari-ous influences of parameters on vibration characteristics is crucial when employing the axial time-delay velocity feedback strategy to suppress galloping.Therefore,to achieve the best vibration suppression effect,it is crucial to adjust the time-delay parameter for modifying the range and amplitude of the resonance zone.The conclusions obtained by this study are expected to advance the refinement of active control techniques for iced transmission lines,and may provide valuable insights for practical engineering applications.展开更多
Turbulence is expected to play a relevant role in the so-called conductor gallop phenomena,namely,the high-amplitude,low-frequency oscillation of overhead power lines due to the formation of ice structures and the ens...Turbulence is expected to play a relevant role in the so-called conductor gallop phenomena,namely,the high-amplitude,low-frequency oscillation of overhead power lines due to the formation of ice structures and the ensu-ing effect that wind can have on these.In this work,the galloping time history of a wire with distorted(fixed in time)shape due to the formation of ice is analyzed numerically in the frame of afluid-solid coupling method for different wind speeds and levels of turbulence.The results show that the turbulence intensity has a moderate effect on the increase of the conductor’s aerodynamic lift and drag coefficients due to ice accretion;nevertheless,the corresponding changes in the torsion coefficient are very significant and complicated.A high turbulence intensity can affect the torsion coefficient in a certain range of attack angles and increase the torsion angle of the conductor.Through comparison of the galloping phenomena for different wind velocities,it is found that the related amplitude grows significantly with an increase of the wind speed.For a relatively large wind speed,the galloping amplitude is more sensitive to the turbulence intensity.Moreover,the larger the turbulence intensity,the larger the conductor’s vertical and horizontal galloping amplitudes after icing.The torsion angle also increases with an increase in the wind speed and turbulence intensity.展开更多
High-voltage transmission line possesses a typical suspended cable structure that produces ice in harsh weather.Moreover,transversely galloping will be excited due to the irregular structure resulting from the alterna...High-voltage transmission line possesses a typical suspended cable structure that produces ice in harsh weather.Moreover,transversely galloping will be excited due to the irregular structure resulting from the alternation of lift force and drag force.In this paper,the nonlinear dynamics and internal resonance of an iced cable under wind excitation are investigated.Considering the excitation caused by pulsed wind and the movement of the support,the nonlinear governing equations of motion of the iced cable are established using a three-degree-of-freedom model based on Hamilton's principle.By the Galerkin method,the partial differential equations are then discretized into ordinary differential equations.The method of multiple scales is then used to obtain the averaged equations of the iced cable,and the principal parametric resonance-1/2 subharmonic resonance and the 2:1 internal resonance are considered.The numerical simulations are performed to investigate the dynamic response of the iced cable.It is found that there exist periodic,multi-periodic,and chaotic motions of the iced cable subjected to wind excitation.展开更多
Based on the principle of virtual work, an updated Lagrangian finite element formulation for the geometrical large deformation analysis of galloping of the iced conductor in an overhead transmission line is developed....Based on the principle of virtual work, an updated Lagrangian finite element formulation for the geometrical large deformation analysis of galloping of the iced conductor in an overhead transmission line is developed. In numerical simulation, a three-node isoparametric cable element with three translational and one torsional degrees-of-freedom at each node is used to discretize the transmission line. The nonlinear dynamic system equation is solved with the Newmark time integration method and the Newton-Raphson nonlinear iteration. Numerical examples demonstrate the efficiency of the presented method and the developed finite element program. A new possible galloping mode, which may reflect the saturation phenomenon of a nonlinear dynamic system, is discovered under the condition that the lowest order of vertical natural frequency of the transmission line is approximately two times of the horizontal one.展开更多
I's a hot summer day.You're thirsty.You need a cold drink.What do you choose?Many people like lemonade.It is just lemon juice,water and sugar.But some people put berries in it.Blueberry or strawberry lemonade ...I's a hot summer day.You're thirsty.You need a cold drink.What do you choose?Many people like lemonade.It is just lemon juice,water and sugar.But some people put berries in it.Blueberry or strawberry lemonade is delicious.Iced tea is another popular summer drink.You can drink it with or without sugar.Many people also like iced coffee or cold brew coffee.Or you can just have a tall glass of cool water!展开更多
High-resolution observations of short-term changes in sea ice are critical to understanding ice dynamics and also provide important information used in advice to shipping,especially in the Arctic.Although individual s...High-resolution observations of short-term changes in sea ice are critical to understanding ice dynamics and also provide important information used in advice to shipping,especially in the Arctic.Although individual satellite sensors provide periodic sea ice obser-vations with spatial resolutions of tens of meters,information regarding changes that occur over short time intervals of minutes or hours is limited.In this study,a gridded ice-water classification dataset with a high temporal resolution was developed based on observations acquired by multiple satellite sensors in the Marginal Ice Zone(MIZ).This dataset-DynIceData-which combines Sentinel-1 Synthetic Aperture Radar(SAR)data with Gaofen-3(GF-3)SAR and SDGSAT-1 thermal infrared imagery was used to obtain observations of the MIZ with a range of temporal resolutions ran-ging from minutes to tens of hours.The areas of the Arctic covered include the Kara Sea,Beaufort Sea,and Greenland Sea during the period from August 2021 to August 2022.Object-oriented segmen-tation and thresholding were used to obtain the ice-water classifi-cation map from Sentinel-1 and GF-3 SAR image pairs and Sentinel-1 SAR and SDGSAT-1 thermal image pairs.The time interval between the images in each pair ranged from 1 minute to 68 hours.Ten-kilometer grid sample granules with a spatial resolution of 25 m for the GF-3 SAR data and 30 m for the SDGSAT-1 thermal data were used.The classification was verified as having an overall accuracy of at least 95.58%.The DynIceData dataset consists of 7338 samples,which could be used as reference data for further research on rapid changes in sea ice patterns at different short time scales and provide support for research on thermodynamic and dynamic models of sea ice in combination with other environmen-tal data,thus potentially improving the accuracy of sea ice forecast-ing using Artificial Intelligence.The dataset can be accessed at https://doi.org/10.57760/sciencedb.j00001.00784.展开更多
近年来全球极端低温天气频发,严重影响了茶树的产量和品质。ICE(Inducer of CBF expression)基因家族主要参与植物的低温胁迫响应,但在茶树领域中的相关研究还不够全面。本研究从茶树基因组中鉴定出51个茶树CsICEs基因,对其理化性质、...近年来全球极端低温天气频发,严重影响了茶树的产量和品质。ICE(Inducer of CBF expression)基因家族主要参与植物的低温胁迫响应,但在茶树领域中的相关研究还不够全面。本研究从茶树基因组中鉴定出51个茶树CsICEs基因,对其理化性质、基因结构和启动子顺式作用元件展开生物信息学分析。茶树CsICEs基因的启动子区域富含光响应、植物激素、生长发育及非生物胁迫相关顺式作用元件,其可能参与多种逆境胁迫响应。转录组分析和RT-qPCR验证结果发现,低温下CsICE43基因的表达量上升了4.24倍,其可能与茶树低温响应相关。以茶树品种‘保靖黄金茶1号’的cDNA为模板,克隆获得了CsICE43基因,其在不同组织中的表达模式存在差异,在顶芽和嫩叶中特异性高表达。蛋白氨基酸序列和系统进化树分析表明,CsICE43基因包含与ICE家族其他成员一致的S-rich、bHLH、ACT等保守结构域,且与毛花猕猴桃(Actinidiaeriantha)的亲缘关系较近。在STRING在线网站中以拟南芥AtICEs为模型,推测茶树CsICE43蛋白与HOS1、MYB15、DREB1/2存在潜在的互作关系。亚细胞定位试验表明CsICE43定位于细胞核,与跨膜结构分析结果一致。综上所述,本研究发现CsICE43基因可能与茶树低温响应关联,为深入挖掘其基因功能与抗寒分子机理提供了一定的理论基础。展开更多
为探究ICE(inducer of CBF expression)转录因子在高丛蓝莓花果发育进程中可能的调控机制,通过对VcICE基因家族进行全基因组鉴定及生物信息学分析,采用实时荧光定量PCR(qRT-PCR)技术分析VcICE基因亚家族成员在蓝莓花芽膨大和果实发育进...为探究ICE(inducer of CBF expression)转录因子在高丛蓝莓花果发育进程中可能的调控机制,通过对VcICE基因家族进行全基因组鉴定及生物信息学分析,采用实时荧光定量PCR(qRT-PCR)技术分析VcICE基因亚家族成员在蓝莓花芽膨大和果实发育进程中的相对表达水平.结果表明:在高丛蓝莓‘Draper’基因组中鉴定出8个VcICE成员,系统进化分析将其划分为2个亚家族,各亚家族成员均包含S-rich,bHLH和ACT等保守结构域;VcICE基因启动子区域富含光响应、植物激素、生长发育及非生物胁迫相关顺式作用元件;VcICE亚家族基因在高丛蓝莓‘O’Neal’和‘Bluerain’花芽膨大与果实发育进程中的相对表达差异显著.研究结果以期为深入了解VcICE转录因子在蓝莓花果发育进程中的功能提供理论参考.展开更多
Hard carbon(HC)is widely used in sodium-ion batteries(SIBs),but its performance has always been limited by lowinitial Coulombic efficiency(ICE)and cycling stability.Cathode compensation agent is a favorable strategy t...Hard carbon(HC)is widely used in sodium-ion batteries(SIBs),but its performance has always been limited by lowinitial Coulombic efficiency(ICE)and cycling stability.Cathode compensation agent is a favorable strategy to make up for the loss of active sodium ions consumed byHCanode.Yet it lacks agent that effectively decomposes to increase the active sodium ions as well as regulate carbon defects for decreasing the irreversible sodium ions consumption.Here,we propose 1,2-dihydroxybenzene Na salt(NaDB)as a cathode compensation agent with high specific capacity(347.9 mAh g^(-1)),lower desodiation potential(2.4–2.8 V)and high utilization(99%).Meanwhile,its byproduct could functionalize HC with more C=O groups and promote its reversible capacity.Consequently,the presodiation hard carbon(pHC)anode exhibits highly reversible capacity of 204.7 mAh g^(-1) with 98%retention at 5 C rate over 1000 cycles.Moreover,with 5 wt%NaDB initially coated on the Na3V2(PO4)3(NVP)cathode,the capacity retention of NVP + NaDB|HC cell could increase from 22%to 89%after 1000 cycles at 1 C rate.This work provides a new avenue to improve reversible capacity and cycling performance of SIBs through designing functional cathode compensation agent.展开更多
Drought across Northwest China in late spring has exerted a vital effect on the local climate and agricultural production,and has been alleviated during the past decades.This study explored the influence of the preced...Drought across Northwest China in late spring has exerted a vital effect on the local climate and agricultural production,and has been alleviated during the past decades.This study explored the influence of the preceding Arctic sea ice on the May drought in Northwest China caused by the precipitation deficit.Further analysis indicated that when the Greenland Sea ice concentration is abnormally high during February to April,the dry conditions in Northwest China tend to be alleviated.The increase of sea ice in the Greenland Sea can excite a meridional circulation,which causes sea surface temperature(SST)anomalies in the North Atlantic via the sea-air interaction,manifested as significant warm SST anomalies over the south of Greenland and the subtropical North Atlantic,but negative SST anomalies over the west of the Azores.This abnormal SST pattern maintains to May and triggers a zonal wave train from the North Atlantic through Scandinavia and Central Asia to Northwest China,leading to abnormal cyclones in Northwest China.Consequently,Northwest China experiences a more humid climate than usual.展开更多
As one of the strongest convection bands in the Southern Hemisphere,the South Pacific Convergence Zone(SPCZ)substantially influences the variabilities in the atmospheric circulation and Antarctic climate.In this study...As one of the strongest convection bands in the Southern Hemisphere,the South Pacific Convergence Zone(SPCZ)substantially influences the variabilities in the atmospheric circulation and Antarctic climate.In this study,it is revealed that the intensity of the SPCZ can change the characteristics of sea ice in the West Antarctica during austral autumn,which is significantly independent of the El Niño-Southern Oscillation(ENSO).Observational and numerical results suggest that a stronger-than-usual SPCZ can generate a poleward-propagating Rossby wave train along a great circular route and induce a weakening of the Amundsen Sea Low(ASL)near West Antarctica,which may somewhat offset the teleconnections exerted by ENSO.These changes in the strength and zonal extent of ASL is noticeable and robustly lead to a tripole response of sea-ice perturbations in the Ross,Amundsen,and Weddell Seas.We find that the wind-driven dynamical processes determine the local sea-ice changes,while the influence from thermodynamic processes is trivial.This research underscores the need to consider the SPCZ variability for a comprehensive understanding of sea-ice changes in West Antarctica on interannual timescales.展开更多
Ice-breaking methods have become increasingly significant with the ongoing development of the polar regions.Among many ice-breaking methods,ice-breaking that utilizes a moving load is unique compared with the common c...Ice-breaking methods have become increasingly significant with the ongoing development of the polar regions.Among many ice-breaking methods,ice-breaking that utilizes a moving load is unique compared with the common collision or impact methods.A moving load can generate flexural-gravity waves(FGWs),under the influence of which the ice sheet undergoes deformation and may even experience structural damage.Moving loads can be divided into above-ice loads and underwater loads.For the above-ice loads,we discuss the characteristics of the FGWs generated by a moving load acting on a complete ice sheet,an ice sheet with a crack,and an ice sheet with a lead of open water.For underwater loads,we discuss the influence on the ice-breaking characteristics of FGWs of the mode of motion,the geometrical features,and the trajectory of motion of the load.In addition to discussing the status of current research and the technical challenges of ice-breaking by moving loads,this paper also looks ahead to future research prospects and presents some preliminary ideas for consideration.展开更多
The heat content(HC)of water masses on the Ross Sea continental shelf plays an important role in regulating the circulations and the basal melting of the Ross Ice Shelf(RIS).Yet,the evolution of the HC on the Ross Sea...The heat content(HC)of water masses on the Ross Sea continental shelf plays an important role in regulating the circulations and the basal melting of the Ross Ice Shelf(RIS).Yet,the evolution of the HC on the Ross Sea continental shelf is still not clear due to the sparsity of observations.By employing a coupled regional ocean-sea ice-ice shelf model for the Ross Sea,this study analyzes the heat budget of water masses over the continental shelf and in the RIS cavity.According to the topographic features and the HC density,the continental shelf region is divided into 17 subdomains.The heat budget of the middle layer for every subdomain is analyzed.In addition,the heat budget for the RIS cavity is assessed for the first time.Owing to Modified Circumpolar Deep Water intrusion,water masses over the eastern shelf are warmer than over the western shelf,with the coldest water identified in the southwestern inner shelf.The horizontal heat flux mainly provides heat to the continental shelf,while the atmospheric forcing tends to warm up the ocean during the ice-melting period and cool down the ocean during the ice-freezing period.The vertical heat flux is generally upward and transports heat from the deep layer to the upper layer.In the RIS cavity,the seasonal cycle of the HC is dominated by the horizontal flux across the RIS front rather than the basal thermal forcing of the RIS.展开更多
As a crucial component of the Earth’s climate system,Antarctic sea ice has demonstrated significant variability over the satellite era.Here,we identify a remarkable decadal transition in the total Antarctic Sea Ice E...As a crucial component of the Earth’s climate system,Antarctic sea ice has demonstrated significant variability over the satellite era.Here,we identify a remarkable decadal transition in the total Antarctic Sea Ice Extent(SIE).The stage from 1979 to 2006 is characterized by high-frequency(i.e.,seasonal to interannual)temporal variability in SIE and zonal asymmetry in Sea Ice Concentration(SIC),which is primarily under the control of the Amundsen Sea Low(ASL).After 2007,however,sea ice changes exhibit a more spatially homogeneous pattern in SIC and a more temporally long-lasting mode in SIE.Further analysis reveals that sea ice-ocean interaction plays a major role in the low-frequency(i.e.,multiannual)variability of Antarctic sea ice from 2007−22.The related physical process is inferred to manifest as a strong coupling between the surface and the subsurface ocean layers,involving enhanced vertical convection and the downward delivery of the surface anomalies related to ice melting and freezing processes,thus maintaining the SIE anomalies for a longer time.Furthermore,this process mainly occurs in the Amundsen-Bellingshausen Sea(ABS)sector,and the weakened subsurface ocean stratification is the key factor triggering the coupling process in this region.We find that the Circumpolar Deep Water(CDW)over the ABS sector continued to shoal before 2007 and remained stable thereafter.It is speculated that the shoaling of the CDW may be a possible driver leading to the weakening of the subsurface stratification.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51507106)China Postdoctoral Science Foundation(Grant No.2021M702371)。
文摘To ensure the safety of power energy transmission channel and mitigate the harm caused by galloping of iced transmission lines,the axial time-delay velocity feedback strategy is adopted to suppress the galloping.The par-tial differential equation of galloping with axial time-delay velocity feedback strategy is established based on the variational principle for Hamiltonian.Then,the partial differential equation of galloping is transformed into or-dinary differential equation based on normalization and the Galerkin method.The primary amplitude-frequency response equation,the first-order steady-state approximate solution,and the harmonic amplitude-frequency re-sponse equation are derived by the multiscale method.The impact of different parameters such as time-delay value,control coefficient,and amplitude of external excitation on the galloping response are analyzed.The am-plitude under the primary resonance exhibits periodicity as time-delay value varies.The amplitude diminishes with increased control coefficient and increases with external excitation.Comprehensive consideration of vari-ous influences of parameters on vibration characteristics is crucial when employing the axial time-delay velocity feedback strategy to suppress galloping.Therefore,to achieve the best vibration suppression effect,it is crucial to adjust the time-delay parameter for modifying the range and amplitude of the resonance zone.The conclusions obtained by this study are expected to advance the refinement of active control techniques for iced transmission lines,and may provide valuable insights for practical engineering applications.
基金This work was supported in part by the National Natural Science Foundation of China[Grant No.51867013].
文摘Turbulence is expected to play a relevant role in the so-called conductor gallop phenomena,namely,the high-amplitude,low-frequency oscillation of overhead power lines due to the formation of ice structures and the ensu-ing effect that wind can have on these.In this work,the galloping time history of a wire with distorted(fixed in time)shape due to the formation of ice is analyzed numerically in the frame of afluid-solid coupling method for different wind speeds and levels of turbulence.The results show that the turbulence intensity has a moderate effect on the increase of the conductor’s aerodynamic lift and drag coefficients due to ice accretion;nevertheless,the corresponding changes in the torsion coefficient are very significant and complicated.A high turbulence intensity can affect the torsion coefficient in a certain range of attack angles and increase the torsion angle of the conductor.Through comparison of the galloping phenomena for different wind velocities,it is found that the related amplitude grows significantly with an increase of the wind speed.For a relatively large wind speed,the galloping amplitude is more sensitive to the turbulence intensity.Moreover,the larger the turbulence intensity,the larger the conductor’s vertical and horizontal galloping amplitudes after icing.The torsion angle also increases with an increase in the wind speed and turbulence intensity.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11290152,11427801,and 11902220)the Funding Project for Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality,China(PHRIHLB).
文摘High-voltage transmission line possesses a typical suspended cable structure that produces ice in harsh weather.Moreover,transversely galloping will be excited due to the irregular structure resulting from the alternation of lift force and drag force.In this paper,the nonlinear dynamics and internal resonance of an iced cable under wind excitation are investigated.Considering the excitation caused by pulsed wind and the movement of the support,the nonlinear governing equations of motion of the iced cable are established using a three-degree-of-freedom model based on Hamilton's principle.By the Galerkin method,the partial differential equations are then discretized into ordinary differential equations.The method of multiple scales is then used to obtain the averaged equations of the iced cable,and the principal parametric resonance-1/2 subharmonic resonance and the 2:1 internal resonance are considered.The numerical simulations are performed to investigate the dynamic response of the iced cable.It is found that there exist periodic,multi-periodic,and chaotic motions of the iced cable subjected to wind excitation.
基金supported by the Science Foundation of the State Grid Corporation of China (No. 2007-1-77)the Natural Science Foundation Project of CQ CSTC of China (No. 2006BB6149)
文摘Based on the principle of virtual work, an updated Lagrangian finite element formulation for the geometrical large deformation analysis of galloping of the iced conductor in an overhead transmission line is developed. In numerical simulation, a three-node isoparametric cable element with three translational and one torsional degrees-of-freedom at each node is used to discretize the transmission line. The nonlinear dynamic system equation is solved with the Newmark time integration method and the Newton-Raphson nonlinear iteration. Numerical examples demonstrate the efficiency of the presented method and the developed finite element program. A new possible galloping mode, which may reflect the saturation phenomenon of a nonlinear dynamic system, is discovered under the condition that the lowest order of vertical natural frequency of the transmission line is approximately two times of the horizontal one.
文摘I's a hot summer day.You're thirsty.You need a cold drink.What do you choose?Many people like lemonade.It is just lemon juice,water and sugar.But some people put berries in it.Blueberry or strawberry lemonade is delicious.Iced tea is another popular summer drink.You can drink it with or without sugar.Many people also like iced coffee or cold brew coffee.Or you can just have a tall glass of cool water!
基金funded by the National Key Research and Development Program of China(No.2019YFE0105700 and No.2017YFE0111700)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA19070201 and No.XDA19070102)+1 种基金the Innovative Research Program of the International Research Center of Big Data for Sustainable Development Goals(No.CBAS2022IRP08)the International Partnership Program of the Chinese Academy of Sciences“Remote Sensing and Modeling of the Snow and Ice Physical Process”(RSMSIP No.313GJHZ2022054MI).
文摘High-resolution observations of short-term changes in sea ice are critical to understanding ice dynamics and also provide important information used in advice to shipping,especially in the Arctic.Although individual satellite sensors provide periodic sea ice obser-vations with spatial resolutions of tens of meters,information regarding changes that occur over short time intervals of minutes or hours is limited.In this study,a gridded ice-water classification dataset with a high temporal resolution was developed based on observations acquired by multiple satellite sensors in the Marginal Ice Zone(MIZ).This dataset-DynIceData-which combines Sentinel-1 Synthetic Aperture Radar(SAR)data with Gaofen-3(GF-3)SAR and SDGSAT-1 thermal infrared imagery was used to obtain observations of the MIZ with a range of temporal resolutions ran-ging from minutes to tens of hours.The areas of the Arctic covered include the Kara Sea,Beaufort Sea,and Greenland Sea during the period from August 2021 to August 2022.Object-oriented segmen-tation and thresholding were used to obtain the ice-water classifi-cation map from Sentinel-1 and GF-3 SAR image pairs and Sentinel-1 SAR and SDGSAT-1 thermal image pairs.The time interval between the images in each pair ranged from 1 minute to 68 hours.Ten-kilometer grid sample granules with a spatial resolution of 25 m for the GF-3 SAR data and 30 m for the SDGSAT-1 thermal data were used.The classification was verified as having an overall accuracy of at least 95.58%.The DynIceData dataset consists of 7338 samples,which could be used as reference data for further research on rapid changes in sea ice patterns at different short time scales and provide support for research on thermodynamic and dynamic models of sea ice in combination with other environmen-tal data,thus potentially improving the accuracy of sea ice forecast-ing using Artificial Intelligence.The dataset can be accessed at https://doi.org/10.57760/sciencedb.j00001.00784.
文摘近年来全球极端低温天气频发,严重影响了茶树的产量和品质。ICE(Inducer of CBF expression)基因家族主要参与植物的低温胁迫响应,但在茶树领域中的相关研究还不够全面。本研究从茶树基因组中鉴定出51个茶树CsICEs基因,对其理化性质、基因结构和启动子顺式作用元件展开生物信息学分析。茶树CsICEs基因的启动子区域富含光响应、植物激素、生长发育及非生物胁迫相关顺式作用元件,其可能参与多种逆境胁迫响应。转录组分析和RT-qPCR验证结果发现,低温下CsICE43基因的表达量上升了4.24倍,其可能与茶树低温响应相关。以茶树品种‘保靖黄金茶1号’的cDNA为模板,克隆获得了CsICE43基因,其在不同组织中的表达模式存在差异,在顶芽和嫩叶中特异性高表达。蛋白氨基酸序列和系统进化树分析表明,CsICE43基因包含与ICE家族其他成员一致的S-rich、bHLH、ACT等保守结构域,且与毛花猕猴桃(Actinidiaeriantha)的亲缘关系较近。在STRING在线网站中以拟南芥AtICEs为模型,推测茶树CsICE43蛋白与HOS1、MYB15、DREB1/2存在潜在的互作关系。亚细胞定位试验表明CsICE43定位于细胞核,与跨膜结构分析结果一致。综上所述,本研究发现CsICE43基因可能与茶树低温响应关联,为深入挖掘其基因功能与抗寒分子机理提供了一定的理论基础。
文摘为探究ICE(inducer of CBF expression)转录因子在高丛蓝莓花果发育进程中可能的调控机制,通过对VcICE基因家族进行全基因组鉴定及生物信息学分析,采用实时荧光定量PCR(qRT-PCR)技术分析VcICE基因亚家族成员在蓝莓花芽膨大和果实发育进程中的相对表达水平.结果表明:在高丛蓝莓‘Draper’基因组中鉴定出8个VcICE成员,系统进化分析将其划分为2个亚家族,各亚家族成员均包含S-rich,bHLH和ACT等保守结构域;VcICE基因启动子区域富含光响应、植物激素、生长发育及非生物胁迫相关顺式作用元件;VcICE亚家族基因在高丛蓝莓‘O’Neal’和‘Bluerain’花芽膨大与果实发育进程中的相对表达差异显著.研究结果以期为深入了解VcICE转录因子在蓝莓花果发育进程中的功能提供理论参考.
基金supported by National Natural Science Foundation of China(No.22278308 and 22109114)Open Foundation of Shanghai Jiao Tong University Shaoxing Research Institute of Renewable Energy and Molecular Engineering(Grant number:JDSX2022023).
文摘Hard carbon(HC)is widely used in sodium-ion batteries(SIBs),but its performance has always been limited by lowinitial Coulombic efficiency(ICE)and cycling stability.Cathode compensation agent is a favorable strategy to make up for the loss of active sodium ions consumed byHCanode.Yet it lacks agent that effectively decomposes to increase the active sodium ions as well as regulate carbon defects for decreasing the irreversible sodium ions consumption.Here,we propose 1,2-dihydroxybenzene Na salt(NaDB)as a cathode compensation agent with high specific capacity(347.9 mAh g^(-1)),lower desodiation potential(2.4–2.8 V)and high utilization(99%).Meanwhile,its byproduct could functionalize HC with more C=O groups and promote its reversible capacity.Consequently,the presodiation hard carbon(pHC)anode exhibits highly reversible capacity of 204.7 mAh g^(-1) with 98%retention at 5 C rate over 1000 cycles.Moreover,with 5 wt%NaDB initially coated on the Na3V2(PO4)3(NVP)cathode,the capacity retention of NVP + NaDB|HC cell could increase from 22%to 89%after 1000 cycles at 1 C rate.This work provides a new avenue to improve reversible capacity and cycling performance of SIBs through designing functional cathode compensation agent.
基金supported by the National Natural Science Foun-dation of China [grant numbers 41991281 and 42005028]。
文摘Drought across Northwest China in late spring has exerted a vital effect on the local climate and agricultural production,and has been alleviated during the past decades.This study explored the influence of the preceding Arctic sea ice on the May drought in Northwest China caused by the precipitation deficit.Further analysis indicated that when the Greenland Sea ice concentration is abnormally high during February to April,the dry conditions in Northwest China tend to be alleviated.The increase of sea ice in the Greenland Sea can excite a meridional circulation,which causes sea surface temperature(SST)anomalies in the North Atlantic via the sea-air interaction,manifested as significant warm SST anomalies over the south of Greenland and the subtropical North Atlantic,but negative SST anomalies over the west of the Azores.This abnormal SST pattern maintains to May and triggers a zonal wave train from the North Atlantic through Scandinavia and Central Asia to Northwest China,leading to abnormal cyclones in Northwest China.Consequently,Northwest China experiences a more humid climate than usual.
基金supported by the National Natural Science Foundation of China(Grant No.42375024).
文摘As one of the strongest convection bands in the Southern Hemisphere,the South Pacific Convergence Zone(SPCZ)substantially influences the variabilities in the atmospheric circulation and Antarctic climate.In this study,it is revealed that the intensity of the SPCZ can change the characteristics of sea ice in the West Antarctica during austral autumn,which is significantly independent of the El Niño-Southern Oscillation(ENSO).Observational and numerical results suggest that a stronger-than-usual SPCZ can generate a poleward-propagating Rossby wave train along a great circular route and induce a weakening of the Amundsen Sea Low(ASL)near West Antarctica,which may somewhat offset the teleconnections exerted by ENSO.These changes in the strength and zonal extent of ASL is noticeable and robustly lead to a tripole response of sea-ice perturbations in the Ross,Amundsen,and Weddell Seas.We find that the wind-driven dynamical processes determine the local sea-ice changes,while the influence from thermodynamic processes is trivial.This research underscores the need to consider the SPCZ variability for a comprehensive understanding of sea-ice changes in West Antarctica on interannual timescales.
基金Supported by the National Natural Science Foundation of China(Nos.52192693,52192690,52371270,U20A20327)the National Key Research and Development Program of China(Nos.2021YFC2803400).
文摘Ice-breaking methods have become increasingly significant with the ongoing development of the polar regions.Among many ice-breaking methods,ice-breaking that utilizes a moving load is unique compared with the common collision or impact methods.A moving load can generate flexural-gravity waves(FGWs),under the influence of which the ice sheet undergoes deformation and may even experience structural damage.Moving loads can be divided into above-ice loads and underwater loads.For the above-ice loads,we discuss the characteristics of the FGWs generated by a moving load acting on a complete ice sheet,an ice sheet with a crack,and an ice sheet with a lead of open water.For underwater loads,we discuss the influence on the ice-breaking characteristics of FGWs of the mode of motion,the geometrical features,and the trajectory of motion of the load.In addition to discussing the status of current research and the technical challenges of ice-breaking by moving loads,this paper also looks ahead to future research prospects and presents some preliminary ideas for consideration.
基金supported by the National Key R&D Program of China (Grant No. 2024YFF0506603)the Independent Research Foundation of the Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) (Grant Nos. SML2023SP201 and SML2021SP306)+2 种基金the Natural Science Foundation of Guangdong Province, China (Grant No. 2024A1515012717)the Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) (Grant Nos. 313021004, 313022009 and 313022001)the Program of Innovation 2030 on Smart Ocean, Zhejiang University
文摘The heat content(HC)of water masses on the Ross Sea continental shelf plays an important role in regulating the circulations and the basal melting of the Ross Ice Shelf(RIS).Yet,the evolution of the HC on the Ross Sea continental shelf is still not clear due to the sparsity of observations.By employing a coupled regional ocean-sea ice-ice shelf model for the Ross Sea,this study analyzes the heat budget of water masses over the continental shelf and in the RIS cavity.According to the topographic features and the HC density,the continental shelf region is divided into 17 subdomains.The heat budget of the middle layer for every subdomain is analyzed.In addition,the heat budget for the RIS cavity is assessed for the first time.Owing to Modified Circumpolar Deep Water intrusion,water masses over the eastern shelf are warmer than over the western shelf,with the coldest water identified in the southwestern inner shelf.The horizontal heat flux mainly provides heat to the continental shelf,while the atmospheric forcing tends to warm up the ocean during the ice-melting period and cool down the ocean during the ice-freezing period.The vertical heat flux is generally upward and transports heat from the deep layer to the upper layer.In the RIS cavity,the seasonal cycle of the HC is dominated by the horizontal flux across the RIS front rather than the basal thermal forcing of the RIS.
基金supported by the National Natural Science Foundation China(Grant No.42176222).
文摘As a crucial component of the Earth’s climate system,Antarctic sea ice has demonstrated significant variability over the satellite era.Here,we identify a remarkable decadal transition in the total Antarctic Sea Ice Extent(SIE).The stage from 1979 to 2006 is characterized by high-frequency(i.e.,seasonal to interannual)temporal variability in SIE and zonal asymmetry in Sea Ice Concentration(SIC),which is primarily under the control of the Amundsen Sea Low(ASL).After 2007,however,sea ice changes exhibit a more spatially homogeneous pattern in SIC and a more temporally long-lasting mode in SIE.Further analysis reveals that sea ice-ocean interaction plays a major role in the low-frequency(i.e.,multiannual)variability of Antarctic sea ice from 2007−22.The related physical process is inferred to manifest as a strong coupling between the surface and the subsurface ocean layers,involving enhanced vertical convection and the downward delivery of the surface anomalies related to ice melting and freezing processes,thus maintaining the SIE anomalies for a longer time.Furthermore,this process mainly occurs in the Amundsen-Bellingshausen Sea(ABS)sector,and the weakened subsurface ocean stratification is the key factor triggering the coupling process in this region.We find that the Circumpolar Deep Water(CDW)over the ABS sector continued to shoal before 2007 and remained stable thereafter.It is speculated that the shoaling of the CDW may be a possible driver leading to the weakening of the subsurface stratification.
