The fatigue behavior of aluminum alloy 7050-T7451 single lap four-bolted joints was studied by high- frequency fatigue test and finite element （FE） methods. The fatigue test results showed that a better enhancement ...The fatigue behavior of aluminum alloy 7050-T7451 single lap four-bolted joints was studied by high- frequency fatigue test and finite element （FE） methods. The fatigue test results showed that a better enhancement of fatigue life was achieved for the joints with highlocked bolts by employing the combinations of cold expansion, interference fit, and clamping force. The fractography revealed that fatigue cracks propagated tortuously; more fatigue micro-cliffs, tearing ridges, lamellar structure were observed, and fatigue striation spacing was simultaneously reduced. The evaluation of residual stress conducted by FE methods confirmed the experimental results and locations of fatigue crack initiation. The extension of fatigue lives can be attributed to the evolution of fatigue damage and effect of beneficial compressive residual stresses around the hole, resulting in the delay of crack initiation, crack deflection, and plasticityinduced crack closure.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.展开更多
Jiuyao,an essential binomial fermenting agent in the huangjiu brewing process,is closely related to the flavor and quality of huangjiu.Meanwhile,microbial terroir is essential to the formation of regional characterist...Jiuyao,an essential binomial fermenting agent in the huangjiu brewing process,is closely related to the flavor and quality of huangjiu.Meanwhile,microbial terroir is essential to the formation of regional characteristics of jiuyao.In this paper,22 types of jiuyao samples were collected from the upstream(US),midstream(MS),and downstream(DS)regions of the Yangtze River,where its production is predominantly located.The analysis of the microbial communities in these samples aimed to uncover distribution patterns associated with geographic locations.The predominant microbial taxa identified across all regions included Bacillus subtilis,Pediococcus pentosaceus,Rhizopus oryzae,Saccharomycopsis fibuligera,and Saccharomyces cerevisiae.PCoA and NMDS analysis showed significant differences(P<0.01)in the bacterial and fungal compositions among the three regions.A total of 23 specific bacterial biomarkers and 24 specific fungal biomarkers were detected in the three groups by LEfSe analysis.Additionally,distance decay curves demonstrated that microbial community similarity decreased with increasing geographic distance.pH,amino nitrogen,reducing sugar,mean annual precipitation and relative humidity were found to have a significant effect on the composition of microbial communities in different jiuyao samples(P<0.05).Correlation analysis identified a significant positive association between glucoamylase activity and certain microbes,including Pseudomonas fluorescens,Wickerhamomyces anomalus,Clavispora lusitaniae,and Geotrichum silvicola(P<0.05).This research lays a theoretical foundation for regional optimization of jiuyao production by elucidating the microbial communities and their variations across the Yangtze River Basin.展开更多
Terpenoid compounds exhibit notable bioactivities,including antibacterial,antiviral,antioxidant,and anticancer properties,while simultaneously serving as critical flavor contributors to fermented beverages.Their struc...Terpenoid compounds exhibit notable bioactivities,including antibacterial,antiviral,antioxidant,and anticancer properties,while simultaneously serving as critical flavor contributors to fermented beverages.Their structural diversity and low sensory thresholds impart unique floral,fruity,and woody aromas to Huangjiu.By augmenting the terpenoid biosynthetic capacity of indigenous microorganisms,this novel strategy for improving Huangjiu quality can enhance its flavor complexity and functional characteristics,thereby advancing its development as a flavor-functionality integrated beverage.However,terpenoid content is inherently limited in traditional fermentation systems.In this study,ultraviolet-atmospheric-pressure room-temperature plasma composite mutagenesis was performed on indigenous high-terpenoid-yielding microorganisms isolated from the Huangjiu-making wheat Qu.The mutagenesis targeted Bacillus subtilis YB4,Streptomyces albus LM1,and Saccharomyces cerevisiae CYY-661 using isopentenyl pyrophosphate as the selective pressure.Genetically stable mutants were isolated using serial passage stability assays.Strain interactions were subsequently characterized via mixed fermentation experiments.Selected mutants were used for the wheat Qu preparation and Huangjiu fermentation.Terpenoid content was quantitatively assessed using gas chromatography-mass spectrometry.This approach successfully generated three high-yield,genetically stable mutants:S.cerevisiae JA9,B.subtilis YA17,and S.albus LA9.Our findings demonstrate a considerable enhancement in microbial terpenoid synthesis,reveal complex strain interactions involving synergistic enhancement and substrate competition,and establish an effective strategy to improve the functional value of Huangjiu.It promotes the development of the Huangjiu industry to-wards a healthier and more diverse flavor direction.展开更多
基金supported by Key Research and Development Plan of Shandong Province, China (2017GGX20140)Natural Science Foundation of Shandong Province, China (No. ZR2014JL031)
文摘The fatigue behavior of aluminum alloy 7050-T7451 single lap four-bolted joints was studied by high- frequency fatigue test and finite element （FE） methods. The fatigue test results showed that a better enhancement of fatigue life was achieved for the joints with highlocked bolts by employing the combinations of cold expansion, interference fit, and clamping force. The fractography revealed that fatigue cracks propagated tortuously; more fatigue micro-cliffs, tearing ridges, lamellar structure were observed, and fatigue striation spacing was simultaneously reduced. The evaluation of residual stress conducted by FE methods confirmed the experimental results and locations of fatigue crack initiation. The extension of fatigue lives can be attributed to the evolution of fatigue damage and effect of beneficial compressive residual stresses around the hole, resulting in the delay of crack initiation, crack deflection, and plasticityinduced crack closure.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.
基金supported by the National Natural Science Foundation of China(22422807)Zhejiang Province-Local Collaborative Innovation Project(2024SDXT001-3)+1 种基金Shaoxing Science and Technology Plan Project(2023B43001)National Treasure Ecological Research Synergetic Innovation Center.
文摘Jiuyao,an essential binomial fermenting agent in the huangjiu brewing process,is closely related to the flavor and quality of huangjiu.Meanwhile,microbial terroir is essential to the formation of regional characteristics of jiuyao.In this paper,22 types of jiuyao samples were collected from the upstream(US),midstream(MS),and downstream(DS)regions of the Yangtze River,where its production is predominantly located.The analysis of the microbial communities in these samples aimed to uncover distribution patterns associated with geographic locations.The predominant microbial taxa identified across all regions included Bacillus subtilis,Pediococcus pentosaceus,Rhizopus oryzae,Saccharomycopsis fibuligera,and Saccharomyces cerevisiae.PCoA and NMDS analysis showed significant differences(P<0.01)in the bacterial and fungal compositions among the three regions.A total of 23 specific bacterial biomarkers and 24 specific fungal biomarkers were detected in the three groups by LEfSe analysis.Additionally,distance decay curves demonstrated that microbial community similarity decreased with increasing geographic distance.pH,amino nitrogen,reducing sugar,mean annual precipitation and relative humidity were found to have a significant effect on the composition of microbial communities in different jiuyao samples(P<0.05).Correlation analysis identified a significant positive association between glucoamylase activity and certain microbes,including Pseudomonas fluorescens,Wickerhamomyces anomalus,Clavispora lusitaniae,and Geotrichum silvicola(P<0.05).This research lays a theoretical foundation for regional optimization of jiuyao production by elucidating the microbial communities and their variations across the Yangtze River Basin.
基金National Key Research and Development Program of China(2022YFD2101204)Zhejiang Province and Local Collaborative Project(2024SDXT001-4)+1 种基金Fundamental Research Funds for Central Univer-sities(JUSRP202401019)National Engineering Research Center of Solid-state Brewing.
文摘Terpenoid compounds exhibit notable bioactivities,including antibacterial,antiviral,antioxidant,and anticancer properties,while simultaneously serving as critical flavor contributors to fermented beverages.Their structural diversity and low sensory thresholds impart unique floral,fruity,and woody aromas to Huangjiu.By augmenting the terpenoid biosynthetic capacity of indigenous microorganisms,this novel strategy for improving Huangjiu quality can enhance its flavor complexity and functional characteristics,thereby advancing its development as a flavor-functionality integrated beverage.However,terpenoid content is inherently limited in traditional fermentation systems.In this study,ultraviolet-atmospheric-pressure room-temperature plasma composite mutagenesis was performed on indigenous high-terpenoid-yielding microorganisms isolated from the Huangjiu-making wheat Qu.The mutagenesis targeted Bacillus subtilis YB4,Streptomyces albus LM1,and Saccharomyces cerevisiae CYY-661 using isopentenyl pyrophosphate as the selective pressure.Genetically stable mutants were isolated using serial passage stability assays.Strain interactions were subsequently characterized via mixed fermentation experiments.Selected mutants were used for the wheat Qu preparation and Huangjiu fermentation.Terpenoid content was quantitatively assessed using gas chromatography-mass spectrometry.This approach successfully generated three high-yield,genetically stable mutants:S.cerevisiae JA9,B.subtilis YA17,and S.albus LA9.Our findings demonstrate a considerable enhancement in microbial terpenoid synthesis,reveal complex strain interactions involving synergistic enhancement and substrate competition,and establish an effective strategy to improve the functional value of Huangjiu.It promotes the development of the Huangjiu industry to-wards a healthier and more diverse flavor direction.
