Many properties of Mg matrix composites are mutually incompatible,and even completely repel each other.Here,we constructed a magnetic layered component in Mg matrix composite reinforced with reduced graphene oxide(RGO...Many properties of Mg matrix composites are mutually incompatible,and even completely repel each other.Here,we constructed a magnetic layered component in Mg matrix composite reinforced with reduced graphene oxide(RGO)through an in-situ interface reaction strategy,achieving simultaneous improvement in the strength,ductility,and electromagnetic shielding performance of the composite.The magnetic component is generated by the in-situ reaction of Fe_(2)O_(3)nanoparticles encapsulated on RGO with the Mg matrix.The superior strength-ductility synergy originates from layered heterostructure,which actives non-basal dislocations and enables a stable microcrackmultiplication.The heterogeneous layered structure strengthens the multi-level reflection of electromagnetic wave(EMW)inside the composite.The in-situ interfacial reaction introduces abundant of heterogeneous interfaces into the composites,which improves the interfacial polarization loss ability of the composites.The magnetic RGO layer can provide shape anisotropy that breaks the Snoek limit,thus improving the magnetic loss ability of composite in high-frequency electromagnetic fields.The synergistic action of multiple EMW loss mechanisms improves the electromagnetic shielding performance of composite.The current study emphasizes the influence of interface structure on the mechanical and functional properties of composites,and presents a promising approach for the development of structure/functional integrated composites with enhanced properties.展开更多
The fatigue cracking behavior at twin boundaries(TBs)in a Co Cr Fe Mn Ni high-entropy alloy with three different grain sizes was systematically investigated under low-cycle fatigue.Irrespective of grain size,the chang...The fatigue cracking behavior at twin boundaries(TBs)in a Co Cr Fe Mn Ni high-entropy alloy with three different grain sizes was systematically investigated under low-cycle fatigue.Irrespective of grain size,the change from slip band cracking to TB cracking occurred with increasing the difference in the Schmid factors(DSF)between matrix and twin.However,the required critical DSF for the transition of the dominant cracking mode decreases with decreasing grain size due to the reduced slip band spacing that increases the impingement sites on the TBs and facilitates the coalescence of defects and voids to initiate TB cracks.展开更多
Lake Chany is the largest endorheic lake in Siberia whose catchment is entirely on the territory of Russia.Its geographical location on the climate-sensitive boundary of wet and dry landscapes provides an opportunity ...Lake Chany is the largest endorheic lake in Siberia whose catchment is entirely on the territory of Russia.Its geographical location on the climate-sensitive boundary of wet and dry landscapes provides an opportunity to gain more knowledge about environmental changes in the West Siberian interior during the Holocene and about the evolution of the lake itself.Sediment cores obtained from the Yarkov subbasin of the lake in 2008 have been comprehensively studied by a number of approaches including sedimentology and AMS dating,pollen,diatom and chironomid analyses(with statistical interpretation of the results),mineralogy of authigenic minerals and geochemistry of plant lipids(biomarker analysis.).Synthesis of new results presented here and published data provides a good justification for our hypothesis that Lake Chany is very young,no older than 3.6 ka BP.Before that,between 9 and 3.6 ka BP,the Chany basin was a swampy landscape with a very low sedimentation rate;it could not be identified as a water body.In the early lake phase,between 3.6 and 1.5 ka BP,the lake was shallow,1.2–3.5 m in depth,and it rose to its modern size,up to 6.5 m in depth,during the last millennium.Our data reveal important changes in the understanding of the history of this large endorheic lake,as before it was envisioned as a large lake with significant changes in water level since ca.14 ka BP.In addition to hydrology,our proxies provide updates and details of the regional vegetation and climate change since ca.4 ka BP in the WestSiberian forest-steppe and steppe.As evolution of the Chany basin is dependent on hydroclimatic changes in a large region of southern West Siberia,we compare lake-level change and climate-change proxies from the other recently and most comprehensively studied lakes of the region.展开更多
Currently,IEC/TC90 is working on standardizing the method for measuring critical current(Ic)in superconducting cables.At the end of 2020,an international round robin test(RRT)was organized,in which five Chinese instit...Currently,IEC/TC90 is working on standardizing the method for measuring critical current(Ic)in superconducting cables.At the end of 2020,an international round robin test(RRT)was organized,in which five Chinese institutions participated,and four accomplished the test.The electric-field versus current(E-I)curves obtained by each institution are highly repeatable.Those obtained by different institutions are nearly identical after appropriate curve averaging,indicating high reproducibility,except the last participant's inner core curves.The discrepancy was later determined to be the result of sample cable damage.After excluding highly deviated data,it is determined that the maximum relative standard uncertainty in I_(c) is 0.7%,and the maximum relative standard uncertainty in n-value is 12.8%.The I_(c)values are comparable to Japan's domestic RRT results,but the n-values are significantly different.The test results support the DC four-terminal method as a recommended test method,with a target relative uncertainty of less than 2%for the Ic value.展开更多
基金supported by Yunnan Major Scientific and Technological Projects(grant No 202202AG050004,202202AG050011)the National Natural Science Foundation of China(grant No 52061021)Yunnan Industrial Technology Innovation Talent Project.
文摘Many properties of Mg matrix composites are mutually incompatible,and even completely repel each other.Here,we constructed a magnetic layered component in Mg matrix composite reinforced with reduced graphene oxide(RGO)through an in-situ interface reaction strategy,achieving simultaneous improvement in the strength,ductility,and electromagnetic shielding performance of the composite.The magnetic component is generated by the in-situ reaction of Fe_(2)O_(3)nanoparticles encapsulated on RGO with the Mg matrix.The superior strength-ductility synergy originates from layered heterostructure,which actives non-basal dislocations and enables a stable microcrackmultiplication.The heterogeneous layered structure strengthens the multi-level reflection of electromagnetic wave(EMW)inside the composite.The in-situ interfacial reaction introduces abundant of heterogeneous interfaces into the composites,which improves the interfacial polarization loss ability of the composites.The magnetic RGO layer can provide shape anisotropy that breaks the Snoek limit,thus improving the magnetic loss ability of composite in high-frequency electromagnetic fields.The synergistic action of multiple EMW loss mechanisms improves the electromagnetic shielding performance of composite.The current study emphasizes the influence of interface structure on the mechanical and functional properties of composites,and presents a promising approach for the development of structure/functional integrated composites with enhanced properties.
基金supported financially by the Australian Research Council(Nos.DE170100053 and DP190102243)the Open Foundation of State Key Laboratory of Powder Metallurgy at Central South University+1 种基金the National Natural Science Foundation of China(No.51771229)The University of Sydney under the Robinson Fellowship Scheme.
文摘The fatigue cracking behavior at twin boundaries(TBs)in a Co Cr Fe Mn Ni high-entropy alloy with three different grain sizes was systematically investigated under low-cycle fatigue.Irrespective of grain size,the change from slip band cracking to TB cracking occurred with increasing the difference in the Schmid factors(DSF)between matrix and twin.However,the required critical DSF for the transition of the dominant cracking mode decreases with decreasing grain size due to the reduced slip band spacing that increases the impingement sites on the TBs and facilitates the coalescence of defects and voids to initiate TB cracks.
基金The biomarker analysis and all organic matter related interpretations were made in favor of the joint Russia-China research project,RFBR no.21-55-53037 and NSFC no.42111530031The lake level changes were investigated in favor of the RFBR project No.19-29-05085+6 种基金Numerical reconstruction of climate was made in the frame of ANSO Collaborative Research(ANSO-CR-PP-2021-02)The contribution by Natalia Rudaya matches interests of the RSF project no.20-17-00110the Tomsk State University Development Program(Priority 2030)financed by National Natural Science Foundation of China(grant no.41988101)the Sino-German Mobility Program(grant no.M-0359)Diatom and chironomid analyses were funded by the RSF project No.20-17-00135Databases developed with the support of the RSF No.22-17-00185 and 22-17-00113 projects were used for quantitative environmental reconstructions(WD and T July)and supplementary statistical research.
文摘Lake Chany is the largest endorheic lake in Siberia whose catchment is entirely on the territory of Russia.Its geographical location on the climate-sensitive boundary of wet and dry landscapes provides an opportunity to gain more knowledge about environmental changes in the West Siberian interior during the Holocene and about the evolution of the lake itself.Sediment cores obtained from the Yarkov subbasin of the lake in 2008 have been comprehensively studied by a number of approaches including sedimentology and AMS dating,pollen,diatom and chironomid analyses(with statistical interpretation of the results),mineralogy of authigenic minerals and geochemistry of plant lipids(biomarker analysis.).Synthesis of new results presented here and published data provides a good justification for our hypothesis that Lake Chany is very young,no older than 3.6 ka BP.Before that,between 9 and 3.6 ka BP,the Chany basin was a swampy landscape with a very low sedimentation rate;it could not be identified as a water body.In the early lake phase,between 3.6 and 1.5 ka BP,the lake was shallow,1.2–3.5 m in depth,and it rose to its modern size,up to 6.5 m in depth,during the last millennium.Our data reveal important changes in the understanding of the history of this large endorheic lake,as before it was envisioned as a large lake with significant changes in water level since ca.14 ka BP.In addition to hydrology,our proxies provide updates and details of the regional vegetation and climate change since ca.4 ka BP in the WestSiberian forest-steppe and steppe.As evolution of the Chany basin is dependent on hydroclimatic changes in a large region of southern West Siberia,we compare lake-level change and climate-change proxies from the other recently and most comprehensively studied lakes of the region.
基金the Strategic Priority Research Program of Chinese Academy of Sciences,Grant No.XDB 2500.
文摘Currently,IEC/TC90 is working on standardizing the method for measuring critical current(Ic)in superconducting cables.At the end of 2020,an international round robin test(RRT)was organized,in which five Chinese institutions participated,and four accomplished the test.The electric-field versus current(E-I)curves obtained by each institution are highly repeatable.Those obtained by different institutions are nearly identical after appropriate curve averaging,indicating high reproducibility,except the last participant's inner core curves.The discrepancy was later determined to be the result of sample cable damage.After excluding highly deviated data,it is determined that the maximum relative standard uncertainty in I_(c) is 0.7%,and the maximum relative standard uncertainty in n-value is 12.8%.The I_(c)values are comparable to Japan's domestic RRT results,but the n-values are significantly different.The test results support the DC four-terminal method as a recommended test method,with a target relative uncertainty of less than 2%for the Ic value.
