Silicon(Si)is an inevitable impurity element in the AZ31 alloy.In this study,the Si impurity was detected mainly as fine Mg_(2)Si particles dispersed widely within the central region of the Mg_(17)Al_(12) phase.During...Silicon(Si)is an inevitable impurity element in the AZ31 alloy.In this study,the Si impurity was detected mainly as fine Mg_(2)Si particles dispersed widely within the central region of the Mg_(17)Al_(12) phase.During the solidification process,the Mg_(2)Si particle precipitates at about 565℃,before the Mg_(17)Al_(12) phase of 186℃,potentially acting as the heterogeneous nucleation core for the Mg_(17)Al_(12) phase.The orientation relationship between Mg_(2)Si and Mg_(17)Al_(12) was investigated using the Edge-to-Edge matching model(E2EM)calculations,which showed a misfit of only 0.1%.This low misfit suggests that Mg_(2)Si can serve as a heterogeneous nucleation site for Mg_(17)Al_(12).The surface and interface structures of Mg_(2)Si(220)and Mg_(17)Al_(12)(332)were constructed,and then investigated through the first-principles calculation.The theoretical results indicate that Mg and Al are easily adsorbed on the surface of Mg_(2)Si,with Al showing higher adsorption energy than Mg.Furthermore,the interface between Mg_(2)Si and Mg_(17)Al_(12) exhibits favorable thermodynamic stability.Combined with experiments and theoretical calculations,it is confirmed that the Mg_(2)Si particles,formed due to the Si impurity,provide effective heterogeneous nucleation sites for the Mg_(17)Al_(12) phase.展开更多
This work studies the trajectory tracking control for unmanned aerial helicopter(UAH)system under both matched disturbance and mismatched ones.Initially,to tackle the strong coupling,an input-output feedback lineariza...This work studies the trajectory tracking control for unmanned aerial helicopter(UAH)system under both matched disturbance and mismatched ones.Initially,to tackle the strong coupling,an input-output feedback linearization method is utilized to simplify the nonlinear UAH system.Secondly,a set of finite-time disturbance observers(FTDOs)are proposed to estimate mismatched disturbances with their successive derivatives,which are utilized to design the feedforward controller via backstepping.Thirdly,as for matched disturbance,by defining the disturbance characterization index(DCI)to determine whether the disturbance is harmful or not for the UAH system,a feedback controller is proposed and a sufficient condition is established to ensure the convergence of the tracking error.Finally,some numerical simulations and comparisons illustrate the validity and advantages of our control scheme.展开更多
Currently,cultivated tea plants are classified into three varieties,namely,Camellia sinensis var.sinensis,C.sinensis var.assamica,and C.sinensis var.kucha.Three tea varieties made green teas(TVGTs)are widely consumed ...Currently,cultivated tea plants are classified into three varieties,namely,Camellia sinensis var.sinensis,C.sinensis var.assamica,and C.sinensis var.kucha.Three tea varieties made green teas(TVGTs)are widely consumed worldwide.However,a comparative investigation of the beneficial effects,mechanism,and characteristic compounds of TVGTs has not been reported.Here,three representative tea plant varieties,namely,C.sinensis var.sinensis cv.Fuding(FD),C.sinensis var.assamica cv.Yunkang 10(YK),and C.sinensis var.kucha(KC),planted in the same garden,were used to make green teas utilizing the same standard procedure.Our findings show that the TVGTs effectively improved hyperglycemia,obesity,dyslipidemia,fatty liver,and mesenteric artery(MA)hypercontractility in mice with diabetes and obesity induced by a high-fat diet(HFD)after 11-and 22-week interventions,with YK being the most effective at 22 weeks.Liver lipidomics indicated that the TVGTs restored the glycerophospholipid and sphingolipid balance and reduced triglycerides,with YK demonstrating superior effects.The TVGTs,particularly YK,suppressed triglyceride synthesis through the ARV1-FXR-SHP-SREBP-1c pathway.A chemical profile analysis revealed that YK green tea had enriched active compounds,including caffeine,quinic acid,L-theanine,gallic acid,and catechins,compared with FD and KC green teas,which may contribute to ameliorating diabetic dyslipidemia via synergistic action.As a representative tea variety of C.sinensis var.assamica,YK green tea was found to be superior to the other two green teas in preventing and treating diabetic dyslipidemia,especially with long term consumption.These data provide important information for tea plant breeders and tea consumers.展开更多
Tea plant is an important economic crop,which is used to produce the world's oldest and most widely consumed tea beverages.Here,we present a high-quality reference genome assembly of the tea plant(Camellia sinensi...Tea plant is an important economic crop,which is used to produce the world's oldest and most widely consumed tea beverages.Here,we present a high-quality reference genome assembly of the tea plant(Camellia sinensis var.sinensis)consisting of 15 pseudo-chromosomes.LTR retrotransposons(LTR-RTs)account for 70.38%of the genome,and we present evidence that LTR-RTS play critical roles in genome size expansion and the transcriptional diversification of tea plant genes through preferential insertion in promoter regions and introns.Genes,particularly those coding for terpene biosynthesis pro-teins,associated with tea aroma and stress resistance were significantly amplified through recent tandem duplications and exist as gene clusters in tea plant genome.Phylogenetic analysis of the sequences of 81 tea plant accessions with diverse origins revealed three well-differentiated tea plant populations,support-ing the proposition for the southwest origin of the Chinese cultivated tea plant and its later spread to western Asia through introduction.Domestication and modern breeding left significant signatures on hundreds of genes in the tea plant genome,particularly those associated with tea quality and stress resis-tance.The genomic sequences of the reported reference and resequenced tea plant accessions provide valuable resources for future functional genomics study and molecular breeding of improved cul-tivars of tea plants.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51871100 and 12074126).
文摘Silicon(Si)is an inevitable impurity element in the AZ31 alloy.In this study,the Si impurity was detected mainly as fine Mg_(2)Si particles dispersed widely within the central region of the Mg_(17)Al_(12) phase.During the solidification process,the Mg_(2)Si particle precipitates at about 565℃,before the Mg_(17)Al_(12) phase of 186℃,potentially acting as the heterogeneous nucleation core for the Mg_(17)Al_(12) phase.The orientation relationship between Mg_(2)Si and Mg_(17)Al_(12) was investigated using the Edge-to-Edge matching model(E2EM)calculations,which showed a misfit of only 0.1%.This low misfit suggests that Mg_(2)Si can serve as a heterogeneous nucleation site for Mg_(17)Al_(12).The surface and interface structures of Mg_(2)Si(220)and Mg_(17)Al_(12)(332)were constructed,and then investigated through the first-principles calculation.The theoretical results indicate that Mg and Al are easily adsorbed on the surface of Mg_(2)Si,with Al showing higher adsorption energy than Mg.Furthermore,the interface between Mg_(2)Si and Mg_(17)Al_(12) exhibits favorable thermodynamic stability.Combined with experiments and theoretical calculations,it is confirmed that the Mg_(2)Si particles,formed due to the Si impurity,provide effective heterogeneous nucleation sites for the Mg_(17)Al_(12) phase.
基金This work was supported by National Natural Science Foundations of China(Nos.62073164,61873127,61922042)the Foundation of Equipment Pre-research Project of Key Laboratory(No.61422200306).
文摘This work studies the trajectory tracking control for unmanned aerial helicopter(UAH)system under both matched disturbance and mismatched ones.Initially,to tackle the strong coupling,an input-output feedback linearization method is utilized to simplify the nonlinear UAH system.Secondly,a set of finite-time disturbance observers(FTDOs)are proposed to estimate mismatched disturbances with their successive derivatives,which are utilized to design the feedforward controller via backstepping.Thirdly,as for matched disturbance,by defining the disturbance characterization index(DCI)to determine whether the disturbance is harmful or not for the UAH system,a feedback controller is proposed and a sufficient condition is established to ensure the convergence of the tracking error.Finally,some numerical simulations and comparisons illustrate the validity and advantages of our control scheme.
基金financially supported by the National Key Research and Development Program of China(2021YFD1601102)by a key joint grant for regional innovation from the National Natural Science Foundation of China(U19A2034)+2 种基金a key grant for University Synergy Innovation Program of Anhui Province(GXXT-2019-49)a grant from the China Agriculture Research System of MOF and MARA(CARS-19)a grant for supporting an animal core facility in Anhui Agricultural University from the Department of Sciences and Technology of Anhui Province.
文摘Currently,cultivated tea plants are classified into three varieties,namely,Camellia sinensis var.sinensis,C.sinensis var.assamica,and C.sinensis var.kucha.Three tea varieties made green teas(TVGTs)are widely consumed worldwide.However,a comparative investigation of the beneficial effects,mechanism,and characteristic compounds of TVGTs has not been reported.Here,three representative tea plant varieties,namely,C.sinensis var.sinensis cv.Fuding(FD),C.sinensis var.assamica cv.Yunkang 10(YK),and C.sinensis var.kucha(KC),planted in the same garden,were used to make green teas utilizing the same standard procedure.Our findings show that the TVGTs effectively improved hyperglycemia,obesity,dyslipidemia,fatty liver,and mesenteric artery(MA)hypercontractility in mice with diabetes and obesity induced by a high-fat diet(HFD)after 11-and 22-week interventions,with YK being the most effective at 22 weeks.Liver lipidomics indicated that the TVGTs restored the glycerophospholipid and sphingolipid balance and reduced triglycerides,with YK demonstrating superior effects.The TVGTs,particularly YK,suppressed triglyceride synthesis through the ARV1-FXR-SHP-SREBP-1c pathway.A chemical profile analysis revealed that YK green tea had enriched active compounds,including caffeine,quinic acid,L-theanine,gallic acid,and catechins,compared with FD and KC green teas,which may contribute to ameliorating diabetic dyslipidemia via synergistic action.As a representative tea variety of C.sinensis var.assamica,YK green tea was found to be superior to the other two green teas in preventing and treating diabetic dyslipidemia,especially with long term consumption.These data provide important information for tea plant breeders and tea consumers.
基金This work was supported by the National Key Research and Development Program of China(2018YFD1000601 and 2019YFD1001601)the National Natural Science Foundation of China(31800180)+2 种基金the Natural Science Foundation of Anhui Province of China(1908085MC75)the China Postdoctoral Science Foundation(2017M621992)and the special funds for tea germplasm garden construction(2060502 and 201834040003).
文摘Tea plant is an important economic crop,which is used to produce the world's oldest and most widely consumed tea beverages.Here,we present a high-quality reference genome assembly of the tea plant(Camellia sinensis var.sinensis)consisting of 15 pseudo-chromosomes.LTR retrotransposons(LTR-RTs)account for 70.38%of the genome,and we present evidence that LTR-RTS play critical roles in genome size expansion and the transcriptional diversification of tea plant genes through preferential insertion in promoter regions and introns.Genes,particularly those coding for terpene biosynthesis pro-teins,associated with tea aroma and stress resistance were significantly amplified through recent tandem duplications and exist as gene clusters in tea plant genome.Phylogenetic analysis of the sequences of 81 tea plant accessions with diverse origins revealed three well-differentiated tea plant populations,support-ing the proposition for the southwest origin of the Chinese cultivated tea plant and its later spread to western Asia through introduction.Domestication and modern breeding left significant signatures on hundreds of genes in the tea plant genome,particularly those associated with tea quality and stress resis-tance.The genomic sequences of the reported reference and resequenced tea plant accessions provide valuable resources for future functional genomics study and molecular breeding of improved cul-tivars of tea plants.
