Rate-dependent inhomogeneous creep behavior in metallic glasses

Creep deformation can be classified as homogeneous flow and inhomogeneous flow in bulk metallic glass(BMG).In order to understand the conversion conditions of the two types of creep deformation,the effect of loading rate on the creep behavior of a Ti_(40)Zr_(10)Cu_(47)Sn_(3)(at.%)BMG at ambient temperature was investigated using nanoindentation and molecular dynamic simulation.Results indicate that at low loading rates,many serrations appear in loading stage,leading to inhomogeneous serrated flow in the creep stage.When the loading rate is high enough,the creep deformation tends to be homogeneous.The related mechanism responsible for the rate-dependent creep behavior is attributed to the number of pre-existing major shear bands which is influenced significantly by the loading rate.

Construction of daily precipitation series and the observational characteristics of extreme precipitation in Tianjin,China during 1888-2022

Given the difficulties in rescuing and ensuring the quality of long-term climate data,current studies on century-scale climate change are usually limited to annual and monthly data,resulting in the poor detection of extreme climate events and their changes before 1950.In this study,we reconstructed a daily precipitation series for Tianjin from 15 September 1887 to 31 December 2022 on the basis of the most comprehensive daily precipitation records collected from the Tianjin Meteorological Archive,China,and in reference to the precipitation analysis results based on the datasets developed by the Climatic Research Unit Time-Series version 4.06,Global Precipitation Climatology Centre and University of Delaware along with the application of various homogenisation methods for climate series.Our approach provides a complete and reliable century-long daily precipitation series for the study of regional or local extreme weather and climate events.The reconstructed daily dataset reveals that the annual precipitation amount and R95 intensity in Tianjin during 1888-2022 lack significant trends and have values of 0.74±6.99 and-1.84±3.22 mm per decade,respectively.On the annual and seasonal scales,the precipitation amount and R95 intensity,particularly those in autumn,have increased since the latter half of the 20th century relative to those in 1888-1950.However,the increase in precipitation amount and R95 intensity is relatively limited compared with that in atmospheric water vapour content due to surface warming,indicating the highly sensitive response of extreme precipitation events to warming.In addition,the estimates for the return periods of 5,10,20,50 and 100 years covering 1888-2022,1888-1950 and 1951-2022 depict that the intensity of heavy rain and above magnitude was highest in 1888-1950 and decreased in 1951-2022.

Arctic warming trends and their uncertainties based on surface temperature reconstruction under different sea ice extent scenarios

IPCC AR6 states that the neglect of recent rapid warming in the Arctic generally leads to an underestimate of global warming trends.In this study,by reconstructing the surface temperature(ST)datasets in the Arctic under different sea ice extent scenarios(Imax and Imin),we respectively evaluated the annual and seasonal warming trends and their uncertainties from 1900 to 2020.The results show that the reconstructed datasets have a good representation of the ST change trends in the Arctic.In 1900e2020,the annual warming trends in the Arctic(0.17±0.031 and 0.14±0.025℃ per decade under the Imax and Imin reconstruction,respectively)are roughly 1.6e1.8 times the global mean warming trends(0.10±0.008 and 0.09±0.008℃ per decade).While in 1979e2020,the Arctic warming trends(0.66±0.100 and 0.55±0.080℃ per decade)increase to 3.1e3.5 times of the global warming trend(0.19±0.023 and 0.18±0.023℃ per decade)for Imax and Imin,respectively,indicating that the Arctic amplification effect has been significantly enhancing in recent decades.Although the seasonal warming trends are closely related to cloud feedback mechanisms,atmospheric circulation,and ocean circulation,they are not sensitive to the different reconstruction scenarios.