nhanced silicate weathering induced by the uplift of the Himalayan-Tibetan Plateau(HTP)has been considered as the major cause of pCO_(2) decline and Cenozoic cooling.However,this hypothesis remains to be validated,lar...nhanced silicate weathering induced by the uplift of the Himalayan-Tibetan Plateau(HTP)has been considered as the major cause of pCO_(2) decline and Cenozoic cooling.However,this hypothesis remains to be validated,largely due to the lack of a reliable reconstruction of the HTP weathering flux.Here,we present a 37-million-year record of the difference in the seawater radiogenic neodymium isotopic composition(△ε_(Nd))of Ocean Drilling Program(ODP)sites and Fe-Mn crusts between the northern and central Indian Ocean,which indicates the contribution of regional weathering input from the South Asian continent to the Indian Ocean.The results show a long-term increase in △ε_(Nd) and thus provide the first critical evidence of enhanced South Asian weathering input since the late Eocene.The evolution coincided well with major pulses of surface uplift in the HTP and global climatic transitions.Our foraminiferal eNd record suggests that tectonic uplift and silicate weathering in South Asia,especially in the Himalayas,might have played a significant role in the late Cenozoic cooling.展开更多
High entropy alloys(HEAs) have presented potential applications in nuclear power plants owing to their novel atomic structure based high irradiation resistance. However, understanding of He-ion irradiation of HEAs is ...High entropy alloys(HEAs) have presented potential applications in nuclear power plants owing to their novel atomic structure based high irradiation resistance. However, understanding of He-ion irradiation of HEAs is still lacking. In this work, we reveal He-ion irradiation resistance of HEA CrMnFeCoNi by comparison study with a pure Ni and a 304 stainless steel(304SS). It is found that the damage structure in the three materials can be characterized with He bubbles and stacking faults/stacking fault tetrahedrons((SFs/SFTs), which show a similar depth distribution after He-ion irradiation at both RT and 450℃.Although the He bubbles have a similar size about 2nm after irradiation at RT, the He bubble sizes of the HEA, 304SS, and Ni increase to 4.0±0.9,5.3±1.0 and 6.7 ±1.0 nm after irradiation at 450℃, respectively. Moreover, the density of SFs/SFTs displays in an order of Ni < 304 SS < HEA at both RT and 450℃.The He-ion irradiation at RT causes significant hardness enhancement for the three materials, however,compared to RT, after irradiation at 450℃, the Ni presents softening, while the 304SS, especially the HEA,shows further hardening. Thus, the HEA CrMnFeCoNi possesses the smallest He bubble size, the densest SFs/SFTs, and the highest hardening, indicating the best structural stability, as well as the best He-ion irradiation resistance, which can be attributed to its low mobility of He atoms and point defects.展开更多
As the second largest dust source on the globe,the tectonic and climatic evolution of continental Asia has an important impact on regional and global climate change.The West Pacific is the main sediment sink for eolia...As the second largest dust source on the globe,the tectonic and climatic evolution of continental Asia has an important impact on regional and global climate change.The West Pacific is the main sediment sink for eolian dust transported eastward from the Asian interior.Clay minerals,as the major fine-grained weathering products of continental rocks,can be readily transported by wind or currents over long distances and thus have been widely used in the reconstruction of paleoclimate and weathering history.However,the overall evolutionary tendency and response mechanism of clay mineral records over large spatial and long timescales across Asia remain unclear.Here,two continuous and high-resolution clay mineral records since 30 Ma were reconstructed from sediments at Deep Sea Drilling Program(DSDP)Sites 292 and 296 in the Philippine Sea.Clay minerals and Sr-Nd isotope compositions were used to constrain provenance and reconstruct the drying history of the dust source region since the Oligocene.The results show that the clay-sized detrital sediments in the Philippine Sea are a mixture of Asian eolian dust and volcanic materials from the West Pacific arcs.Based on the clay mineral compositions and eolian flux,we reveal that the Asian interior has been continuously drying since the late Oligocene and that stepwise enhanced aridification occurred at approximately 20,14,7,and 3 Ma.Compared with other regions of the world,the relative contents of illite and chlorite increased more dramatically in Asia during the late Cenozoic,and the inconsistency became more obvious at approximately 20 Ma.Since 3 Ma,illite and chlorite have increased consistently across the globe.Combined with the Asian tectonic and climatic history,we suggest that the increase in illite and chlorite from Asia between 20 and 3 Ma was mainly in response to the uplift of the Himalayan-Tibetan Plateau,whereas after 3 Ma,it was primarily controlled by global cooling driven by the expansion of the Arctic ice sheet.展开更多
Dear Editor,Theworld had suffered pandemics of COVID-19 caused by SARS-CoV-2.At the time ofwriting,COVID-19 is still widely spreading inmany countries and regions,and by June 14,2022,totally 532,887,351 cases,includin...Dear Editor,Theworld had suffered pandemics of COVID-19 caused by SARS-CoV-2.At the time ofwriting,COVID-19 is still widely spreading inmany countries and regions,and by June 14,2022,totally 532,887,351 cases,including 6,307,021 deaths,were reported globally(WHO,https://covid19.who.int/table).Powerful measures,such as prophylactic and therapeutic interventions against the virus,are in urgent need for COVID-19 control and prevention.The spike protein,which is expressed on the virus surface,is the key determinant of viral-host interaction(Ng et al.,2021)and mediates the virus entry.展开更多
文摘nhanced silicate weathering induced by the uplift of the Himalayan-Tibetan Plateau(HTP)has been considered as the major cause of pCO_(2) decline and Cenozoic cooling.However,this hypothesis remains to be validated,largely due to the lack of a reliable reconstruction of the HTP weathering flux.Here,we present a 37-million-year record of the difference in the seawater radiogenic neodymium isotopic composition(△ε_(Nd))of Ocean Drilling Program(ODP)sites and Fe-Mn crusts between the northern and central Indian Ocean,which indicates the contribution of regional weathering input from the South Asian continent to the Indian Ocean.The results show a long-term increase in △ε_(Nd) and thus provide the first critical evidence of enhanced South Asian weathering input since the late Eocene.The evolution coincided well with major pulses of surface uplift in the HTP and global climatic transitions.Our foraminiferal eNd record suggests that tectonic uplift and silicate weathering in South Asia,especially in the Himalayas,might have played a significant role in the late Cenozoic cooling.
基金supported financially by the "Hundred Talents Project" of Chinese Academy of Sciencesthe "Thousand Youth Talents Plan" of China+1 种基金the National Natural Science Foundation of China (Nos. 51401208 and 51771201)the Shenyang National Laboratory for Materials Science (No. 2017RP17)
文摘High entropy alloys(HEAs) have presented potential applications in nuclear power plants owing to their novel atomic structure based high irradiation resistance. However, understanding of He-ion irradiation of HEAs is still lacking. In this work, we reveal He-ion irradiation resistance of HEA CrMnFeCoNi by comparison study with a pure Ni and a 304 stainless steel(304SS). It is found that the damage structure in the three materials can be characterized with He bubbles and stacking faults/stacking fault tetrahedrons((SFs/SFTs), which show a similar depth distribution after He-ion irradiation at both RT and 450℃.Although the He bubbles have a similar size about 2nm after irradiation at RT, the He bubble sizes of the HEA, 304SS, and Ni increase to 4.0±0.9,5.3±1.0 and 6.7 ±1.0 nm after irradiation at 450℃, respectively. Moreover, the density of SFs/SFTs displays in an order of Ni < 304 SS < HEA at both RT and 450℃.The He-ion irradiation at RT causes significant hardness enhancement for the three materials, however,compared to RT, after irradiation at 450℃, the Ni presents softening, while the 304SS, especially the HEA,shows further hardening. Thus, the HEA CrMnFeCoNi possesses the smallest He bubble size, the densest SFs/SFTs, and the highest hardening, indicating the best structural stability, as well as the best He-ion irradiation resistance, which can be attributed to its low mobility of He atoms and point defects.
基金supported by the National Natural Science Foundation of China(Grant Nos.42125602,42076052)the National Key Research and Development Program of China(Grant No.2022YFF0800503)+3 种基金the Strategic Priority Research Program of CAS(Grant No.XDB40010100)the Marine S&T Fund of Shandong Province for QNLM(Grant No.2022QNLM050203)the Innovation Project of QNLM(Grant No.MGQNLM-KF202001)the Taishan and Aoshan Talents Program(Grant No.2017ASTCP-ES01).
文摘As the second largest dust source on the globe,the tectonic and climatic evolution of continental Asia has an important impact on regional and global climate change.The West Pacific is the main sediment sink for eolian dust transported eastward from the Asian interior.Clay minerals,as the major fine-grained weathering products of continental rocks,can be readily transported by wind or currents over long distances and thus have been widely used in the reconstruction of paleoclimate and weathering history.However,the overall evolutionary tendency and response mechanism of clay mineral records over large spatial and long timescales across Asia remain unclear.Here,two continuous and high-resolution clay mineral records since 30 Ma were reconstructed from sediments at Deep Sea Drilling Program(DSDP)Sites 292 and 296 in the Philippine Sea.Clay minerals and Sr-Nd isotope compositions were used to constrain provenance and reconstruct the drying history of the dust source region since the Oligocene.The results show that the clay-sized detrital sediments in the Philippine Sea are a mixture of Asian eolian dust and volcanic materials from the West Pacific arcs.Based on the clay mineral compositions and eolian flux,we reveal that the Asian interior has been continuously drying since the late Oligocene and that stepwise enhanced aridification occurred at approximately 20,14,7,and 3 Ma.Compared with other regions of the world,the relative contents of illite and chlorite increased more dramatically in Asia during the late Cenozoic,and the inconsistency became more obvious at approximately 20 Ma.Since 3 Ma,illite and chlorite have increased consistently across the globe.Combined with the Asian tectonic and climatic history,we suggest that the increase in illite and chlorite from Asia between 20 and 3 Ma was mainly in response to the uplift of the Himalayan-Tibetan Plateau,whereas after 3 Ma,it was primarily controlled by global cooling driven by the expansion of the Arctic ice sheet.
基金supported by the National Key R&D Program of China(grant number 2020YFC0842600)the National Natural Science Foundation of China (grant numbers 82041038 and 31730029)
文摘Dear Editor,Theworld had suffered pandemics of COVID-19 caused by SARS-CoV-2.At the time ofwriting,COVID-19 is still widely spreading inmany countries and regions,and by June 14,2022,totally 532,887,351 cases,including 6,307,021 deaths,were reported globally(WHO,https://covid19.who.int/table).Powerful measures,such as prophylactic and therapeutic interventions against the virus,are in urgent need for COVID-19 control and prevention.The spike protein,which is expressed on the virus surface,is the key determinant of viral-host interaction(Ng et al.,2021)and mediates the virus entry.
