As the first leading mode of upper-tropospheric circulation in observations, the meridional displacement of the East Asian westerly jet (EAJ) varies closely with the East Asian rainfall in summer. In this study, the i...As the first leading mode of upper-tropospheric circulation in observations, the meridional displacement of the East Asian westerly jet (EAJ) varies closely with the East Asian rainfall in summer. In this study, the interannual variation of the EAJ meridional displacement and its relationship with the East Asian summer rainfall are evaluated, using the historical simulations of CMIP5 (phase 5 of the Coupled Model Intercomparison Project). The models can generally reproduce the meridional displacement of the EAJ, which is mainly manifested as the first principal mode in most of the simulations. For the relationship between the meridional displacement of the EAJ and East Asian rainfall, almost all the models depict a weaker correlation than observations and exhibit considerably large spread across the models. It is found that the discrepancy in the interannual relationship is closely related to the simulation of the climate mean state, including the climatological location of the westerly jet in Eurasia and rainfall bias in South Asia and the western North Pacific. In addition, a close relationship between the simulation discrepancy and intensity of EAJ variability is also found: the models with a stronger intensity of the EAJ meridional displacement tend to reproduce a closer interannual relationship, and vice versa.展开更多
An ideal cerebral aneurysm model with different stent forms is established.By using the single-relaxation-time(SRT)lattice Boltzmann method(LBM)to solve the flow field,the blood flow characteristics in the aneurysm un...An ideal cerebral aneurysm model with different stent forms is established.By using the single-relaxation-time(SRT)lattice Boltzmann method(LBM)to solve the flow field,the blood flow characteristics in the aneurysm under different conditions are studied numerically.The intra-arterial stenting of saccular aneurysms at different Reynolds numbers and the feasibility of new stenting forms such as double stenting and variable-spacing stenting in the aneurysms are explored.The hemodynamic factors such as velocity distribution and wall shear stress(WSS)in the aneurysm are analyzed.Numerical results show that the risk of aneurysm rupture is mainly centralized at the right corner of the aneurysm.Intervention of stents in the aneurysm can effectively reduce the intra-aneurysmal velocity and WSS,and decrease the danger of aneurysm rupture during strenuous exercise or emotional excitement.At the same time,the intervention of a double stent and the stent shape with a dense anterior part in the aneurysm has certain advantages in preventing aneurysm rupture.The intraaneurysmal mean velocity reduction can reach 90.39% and 80.29% after the intervention of the double stent and the anterior densified stent respectively.展开更多
Mechanoredox chemistry that uses highly polarized piezoelectric materials as mechanoredox catalysts to promote redox reactions has emerged recently.It provides an alternative approach alongside the existing polymeriza...Mechanoredox chemistry that uses highly polarized piezoelectric materials as mechanoredox catalysts to promote redox reactions has emerged recently.It provides an alternative approach alongside the existing polymerization methods.Despite recent accomplishments,determining the quantitative relationship between the structure of ZnO and its catalytic performance for polymerization is still challenging.Herein,we prepared various ZnO crystals with different polar facets ratios to achieve efficient mechanically induced reversible addition-fragmentation chain transfer polymerization(mechano-RAFT).ZnO prepared from Zn(NO3)2 showed a high polar facet ratio of 1.66 and offered the highest catalytic activity among all ZnO samples.A near-quantitative initiator efficiency of 99.5%and narrow molecular weight distribution were achieved for the polymerization of n-butyl acrylate.Furthermore,the high chain-end fidelity and chain extension capability were also evidenced by MALDI-TOF MS and GPC analysis.This work highlighted the significant contribution of polar facets in ZnO to its catalytic activity and will guide the design of mechanoredox catalysis with superior catalytic performance in the future.展开更多
Subseasonal to seasonal(S2S)variability represents the atmospheric disturbance on the 10–90-day timescale,which is an important bridge linking weather and climate.In 2015,China Meteorological Administration(CMA)liste...Subseasonal to seasonal(S2S)variability represents the atmospheric disturbance on the 10–90-day timescale,which is an important bridge linking weather and climate.In 2015,China Meteorological Administration(CMA)listed the S2S prediction project that was initiated by WMO programs three years ago as one of its key tasks.After five years of research,significant progress has been made on the mechanisms of the East Asian monsoon(EAM)S2S variability,related impact of climate change,as well as the predictability on the S2S timescale of numerical models.The S2S variability of the EAM is closely linked to extreme persistent climate events in China and is an important target for seasonal climate prediction.However,under the influence of global warming and the interactions among climate systems,the S2S variability of the EAM is so complex that its prediction remains a great challenge.This paper reviews the past achievement and summarizes the recent progress in research of the EAM S2S variability and prediction,including characteristics of the main S2S modes of the EAM,their impact on the extreme events in China,effects of external and internal forcing on the S2S variability,as well as uncertainties of climate models in predicting the S2S variability,with a focus on the progress achieved by the S2S research team of the Chinese Academy of Meteorological Sciences.The present bottlenecks,future directions,and critical research recommendations are also analyzed and presented.展开更多
基金supported by the National Key Research and Development Program of China (Grant No. 2018YFA0606501)the National Natural Science Foundation of China (Grant Nos. 41721004, U1502233 and 41775083)
文摘As the first leading mode of upper-tropospheric circulation in observations, the meridional displacement of the East Asian westerly jet (EAJ) varies closely with the East Asian rainfall in summer. In this study, the interannual variation of the EAJ meridional displacement and its relationship with the East Asian summer rainfall are evaluated, using the historical simulations of CMIP5 (phase 5 of the Coupled Model Intercomparison Project). The models can generally reproduce the meridional displacement of the EAJ, which is mainly manifested as the first principal mode in most of the simulations. For the relationship between the meridional displacement of the EAJ and East Asian rainfall, almost all the models depict a weaker correlation than observations and exhibit considerably large spread across the models. It is found that the discrepancy in the interannual relationship is closely related to the simulation of the climate mean state, including the climatological location of the westerly jet in Eurasia and rainfall bias in South Asia and the western North Pacific. In addition, a close relationship between the simulation discrepancy and intensity of EAJ variability is also found: the models with a stronger intensity of the EAJ meridional displacement tend to reproduce a closer interannual relationship, and vice versa.
基金supported by Management Project of General Hospital of Eastern Theater Command(Grant No.YYBJ2021043)。
文摘An ideal cerebral aneurysm model with different stent forms is established.By using the single-relaxation-time(SRT)lattice Boltzmann method(LBM)to solve the flow field,the blood flow characteristics in the aneurysm under different conditions are studied numerically.The intra-arterial stenting of saccular aneurysms at different Reynolds numbers and the feasibility of new stenting forms such as double stenting and variable-spacing stenting in the aneurysms are explored.The hemodynamic factors such as velocity distribution and wall shear stress(WSS)in the aneurysm are analyzed.Numerical results show that the risk of aneurysm rupture is mainly centralized at the right corner of the aneurysm.Intervention of stents in the aneurysm can effectively reduce the intra-aneurysmal velocity and WSS,and decrease the danger of aneurysm rupture during strenuous exercise or emotional excitement.At the same time,the intervention of a double stent and the stent shape with a dense anterior part in the aneurysm has certain advantages in preventing aneurysm rupture.The intraaneurysmal mean velocity reduction can reach 90.39% and 80.29% after the intervention of the double stent and the anterior densified stent respectively.
基金This work was supported by the National Natural Science Foundation of China(22101195 and 21925107)the Natural Science Foundation of Jiangsu Province(BK20210732)+1 种基金the Suzhou Science&Technology NOVA Program(ZXL2022480)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)and the Program of Innovative Research Team of Soochow University。
文摘Mechanoredox chemistry that uses highly polarized piezoelectric materials as mechanoredox catalysts to promote redox reactions has emerged recently.It provides an alternative approach alongside the existing polymerization methods.Despite recent accomplishments,determining the quantitative relationship between the structure of ZnO and its catalytic performance for polymerization is still challenging.Herein,we prepared various ZnO crystals with different polar facets ratios to achieve efficient mechanically induced reversible addition-fragmentation chain transfer polymerization(mechano-RAFT).ZnO prepared from Zn(NO3)2 showed a high polar facet ratio of 1.66 and offered the highest catalytic activity among all ZnO samples.A near-quantitative initiator efficiency of 99.5%and narrow molecular weight distribution were achieved for the polymerization of n-butyl acrylate.Furthermore,the high chain-end fidelity and chain extension capability were also evidenced by MALDI-TOF MS and GPC analysis.This work highlighted the significant contribution of polar facets in ZnO to its catalytic activity and will guide the design of mechanoredox catalysis with superior catalytic performance in the future.
基金Supported by the National Natural Science Foundation of China(41830969)the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(2019QZKK0105)+2 种基金National Natural Science Foundation of China(42005131)Basic Scientific Research and Operation Fund of the Chinese Academy of Meteorological Sciences(CAMS)(2021Z004)Science and Technology Development Fund of CAMS(2020KJ009 and 2020KJ012)。
文摘Subseasonal to seasonal(S2S)variability represents the atmospheric disturbance on the 10–90-day timescale,which is an important bridge linking weather and climate.In 2015,China Meteorological Administration(CMA)listed the S2S prediction project that was initiated by WMO programs three years ago as one of its key tasks.After five years of research,significant progress has been made on the mechanisms of the East Asian monsoon(EAM)S2S variability,related impact of climate change,as well as the predictability on the S2S timescale of numerical models.The S2S variability of the EAM is closely linked to extreme persistent climate events in China and is an important target for seasonal climate prediction.However,under the influence of global warming and the interactions among climate systems,the S2S variability of the EAM is so complex that its prediction remains a great challenge.This paper reviews the past achievement and summarizes the recent progress in research of the EAM S2S variability and prediction,including characteristics of the main S2S modes of the EAM,their impact on the extreme events in China,effects of external and internal forcing on the S2S variability,as well as uncertainties of climate models in predicting the S2S variability,with a focus on the progress achieved by the S2S research team of the Chinese Academy of Meteorological Sciences.The present bottlenecks,future directions,and critical research recommendations are also analyzed and presented.
