The paper designs a novel material-level specimen and its dedicated fixture suitable for applying Combined high-and low-Cycle Fatigue(CCF)loads.Unlike full-scale or simulation specimens,the CCF specimen eliminates geo...The paper designs a novel material-level specimen and its dedicated fixture suitable for applying Combined high-and low-Cycle Fatigue(CCF)loads.Unlike full-scale or simulation specimens,the CCF specimen eliminates geometrically induced stress gradients in the test region.Experimental data on CCF life and strain responses of ZSGH4169 alloy are acquired under different CCF loads.The Maximum Strain within Each(MSE)CCF cycle is demonstrated to be independent of the Low-Cycle Fatigue(LCF)loads and High-Cycle Fatigue(HCF)stress amplitudes,but exhibits a correlation with the Cycle Ratio of HCF/LCF(Rf).The growth law of MSE changes from linear to logarithmic as Rfdecreases.Strain amplitudes in the dwell stage,observed unaffected by Rf,are quantified as a function of LCF nominal stresses and HCF stress amplitudes.However,under a defined CCF load,strain amplitudes in the dwell stage remain constant.Strain peaks in the dwell stage in a single CCF cycle decrease in a power function with increasing HCF cycles.展开更多
Developing novel building blocks with predictable side-chain orientations and minimal intramolecular interactions is essential for peptide-based self-assembling materials.Traditional structures likeα-helices andβ-sh...Developing novel building blocks with predictable side-chain orientations and minimal intramolecular interactions is essential for peptide-based self-assembling materials.Traditional structures likeα-helices andβ-sheets rely on such interactions for stability,limiting control over exposed interacting moieties.Here,we reported a novel,frame-like peptide scaffold that maintains exceptional stability without intramolecular interactions.This structure exposes its backbone and orients side chains for hierarchical self-assembly into micron-scale cubes.By introducing mutations at specific sites,we controlled packing orientations,offering new options for tunable self-assembly.Our scaffold provides a versatile platform for designing advanced peptide materials,with applications in nanotechnology and biomaterials.展开更多
Pt-rare-earth(PtRE)alloys are considered to be highly promising catalysts for oxygen reduction reaction(ORR)in acidic electrolytes.However,the wet-chemical synthesis of PtRE nanoalloys still faces significant challeng...Pt-rare-earth(PtRE)alloys are considered to be highly promising catalysts for oxygen reduction reaction(ORR)in acidic electrolytes.However,the wet-chemical synthesis of PtRE nanoalloys still faces significant challenges.The precise reaction mechanism for ORR of these catalysts is still unclear on significant aspects involving the rate-determining step and the nature of the ligand effect.Herein,we report a class of solvothermal synthesis of PtRE(RE is Dy or La)nanoalloys.Such PtRE nanoalloys here are active and stable in acidic media,with both high mass activities enhanced by 2-5 times relative to commercial Pt/C catalyst and high stabilities indicative of the little activity decay and negligible structure change after 10,000 cycles.Density functional theory calculations firmly confirm that the ligand effect of RE elements accelerates an O-O bond scission and steers the rate-determining steps from OH^(*)+H^(+)+e-→H_(2)O(on pure Pt surface)to HOOH^(*)+H^(+)+e-→OH^(*)+H_(2)O(on the PtRE nanoalloy surface)for the fast reaction kinetics,which could be fine-tuned by regulating the RE electronic structures and consequently endows the maximal rate of ORR catalysis with PtDy alloy catalysts.展开更多
A uniquely shaped impact structure,the Hailin impact crater,has been discovered in northeast China.The crater was formed on a granodiorite hillside and is an oval depression with asymmetric rim height and a maximum di...A uniquely shaped impact structure,the Hailin impact crater,has been discovered in northeast China.The crater was formed on a granodiorite hillside and is an oval depression with asymmetric rim height and a maximum diameter of 1360 m.The bottom of the crater is filled by Quaternary sediments with large amounts of rock fragments underneath.The discovery of quartz planar deformation features in rock clasts on the crater floor provides diagnostic evidence for the impact origin of the structure.The shape of the crater is largely due to the impact having occurred on a ridge terrain.The impact event probably occurred in the late Cenozoic Era.The Hailin impact crater is the fourth confirmed Chinese impact crater.展开更多
基金co-supported by the National Natural Science Foundation of China(51805017)National Science and Technology Project(J2017-IV-0012-0049)+1 种基金National Science and Technology Project,China(J2019-IV-0007-0075)the Fundamental Research Funds for the Central Universities,China(JKF-20240036).
文摘The paper designs a novel material-level specimen and its dedicated fixture suitable for applying Combined high-and low-Cycle Fatigue(CCF)loads.Unlike full-scale or simulation specimens,the CCF specimen eliminates geometrically induced stress gradients in the test region.Experimental data on CCF life and strain responses of ZSGH4169 alloy are acquired under different CCF loads.The Maximum Strain within Each(MSE)CCF cycle is demonstrated to be independent of the Low-Cycle Fatigue(LCF)loads and High-Cycle Fatigue(HCF)stress amplitudes,but exhibits a correlation with the Cycle Ratio of HCF/LCF(Rf).The growth law of MSE changes from linear to logarithmic as Rfdecreases.Strain amplitudes in the dwell stage,observed unaffected by Rf,are quantified as a function of LCF nominal stresses and HCF stress amplitudes.However,under a defined CCF load,strain amplitudes in the dwell stage remain constant.Strain peaks in the dwell stage in a single CCF cycle decrease in a power function with increasing HCF cycles.
基金supported by the National Basic Research Program of China 973 Program(Nos.2021YFA0910803,2021YFC2103900)the National Natural Science Foundation of China(No.21977011)+4 种基金the Natural Science Foundation of Guangdong Province(Nos.2022A1515010996 and 2020A1515011544)the Shenzhen Science and Technology Innovation Committee(Nos.RCJC20200714114433053,JCYJ20180507181527112 and JCYJ20200109140406047)the Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions(No.2019SHIBS0004)the Shenzhen Fundamental Research Program(No.GXWD20201231165807007–20200827170132001)Tian Fu Jin Cheng Laboratory(Advanced Medical Center)Group Racing Project(No.TFJC2023010008)。
文摘Developing novel building blocks with predictable side-chain orientations and minimal intramolecular interactions is essential for peptide-based self-assembling materials.Traditional structures likeα-helices andβ-sheets rely on such interactions for stability,limiting control over exposed interacting moieties.Here,we reported a novel,frame-like peptide scaffold that maintains exceptional stability without intramolecular interactions.This structure exposes its backbone and orients side chains for hierarchical self-assembly into micron-scale cubes.By introducing mutations at specific sites,we controlled packing orientations,offering new options for tunable self-assembly.Our scaffold provides a versatile platform for designing advanced peptide materials,with applications in nanotechnology and biomaterials.
基金supported by the National Natural Science Foundation of China(No.21975151)China Postdoctoral Science Foundation(No.2023M733452).
文摘Pt-rare-earth(PtRE)alloys are considered to be highly promising catalysts for oxygen reduction reaction(ORR)in acidic electrolytes.However,the wet-chemical synthesis of PtRE nanoalloys still faces significant challenges.The precise reaction mechanism for ORR of these catalysts is still unclear on significant aspects involving the rate-determining step and the nature of the ligand effect.Herein,we report a class of solvothermal synthesis of PtRE(RE is Dy or La)nanoalloys.Such PtRE nanoalloys here are active and stable in acidic media,with both high mass activities enhanced by 2-5 times relative to commercial Pt/C catalyst and high stabilities indicative of the little activity decay and negligible structure change after 10,000 cycles.Density functional theory calculations firmly confirm that the ligand effect of RE elements accelerates an O-O bond scission and steers the rate-determining steps from OH^(*)+H^(+)+e-→H_(2)O(on pure Pt surface)to HOOH^(*)+H^(+)+e-→OH^(*)+H_(2)O(on the PtRE nanoalloy surface)for the fast reaction kinetics,which could be fine-tuned by regulating the RE electronic structures and consequently endows the maximal rate of ORR catalysis with PtDy alloy catalysts.
基金financial support from the Shanghai Key Laboratory Novel Extreme Condition Materials,China(Grant No.22dz2260800)the Shanghai Science and Technology Committee,China(Grant No.22JC1410300)。
文摘A uniquely shaped impact structure,the Hailin impact crater,has been discovered in northeast China.The crater was formed on a granodiorite hillside and is an oval depression with asymmetric rim height and a maximum diameter of 1360 m.The bottom of the crater is filled by Quaternary sediments with large amounts of rock fragments underneath.The discovery of quartz planar deformation features in rock clasts on the crater floor provides diagnostic evidence for the impact origin of the structure.The shape of the crater is largely due to the impact having occurred on a ridge terrain.The impact event probably occurred in the late Cenozoic Era.The Hailin impact crater is the fourth confirmed Chinese impact crater.
