BACKGROUND Formyl peptide receptor 2(Fpr2)is an important receptor in host resistance to bacterial infections.In previous studies,we found that the liver of Fpr2-/-mice is the most severely damaged target organ in blo...BACKGROUND Formyl peptide receptor 2(Fpr2)is an important receptor in host resistance to bacterial infections.In previous studies,we found that the liver of Fpr2-/-mice is the most severely damaged target organ in bloodstream infections,although the reason for this is unclear.AIM To investigate the role of Fpr2 in liver homeostasis and host resistance to bacterial infections.METHODS Transcriptome sequencing was performed on the livers of Fpr2-/-and wild-type(WT)mice.Differentially expressed genes(DEGs)were identified in the Fpr2-/-and WT mice,and the biological functions of DEGs were analyzed by Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis.Quantitative real time-polymerase chain reaction(qRT-PCR)and western blot(WB)analyses were used to further validate the expression levels of differential genes.Cell counting kit-8 assay was employed to investigate cell survival.The cell cycle detection kit was used to measure the distribution of cell cycles.The Luminex assay was used to analyze cytokine levels in the liver.The serum biochemical indices and the number of neutrophils in the liver were measured,and hepatic histopathological analysis was performed.RESULTS Compared with the WT group,445 DEGs,including 325 upregulated genes and 120 downregulated genes,were identified in the liver of Fpr2-/-mice.The enrichment analysis using GO and KEGG showed that these DEGs were mainly related to cell cycle.The qRT-PCR analysis confirmed that several key genes(CycA,CycB1,Cdc20,Cdc25c,and Cdk1)involved in the cell cycle had significant changes.The WB analysis confirmed a decrease in the expression of CDK1 protein.WRW4(an antagonist of Fpr2)could inhibit the proliferation of HepG2 cells in a concentration dependent manner,with an increase in the number of cells in the G0/G1 phase,and a decrease in the number of cells in the S phase.Serum alanine aminotransferase levels increased in Fpr2-/-mice.The Luminex assay measurements showed that interleukin(IL)-10 and chemokine(C-X-C motif)ligand(CXCL)-1 levels were significantly reduced in the liver of Fpr2-/-mice.There was no difference in the number of neutrophils,serum C-reactive protein levels,and liver pathology between WT and Fpr2-/-mice.CONCLUSION Fpr2 participates in the regulation of cell cycle and cell proliferation,and affects the expression of IL-10 and CXCL-1,thus playing an important protective role in maintaining liver homeostasis.展开更多
AIM:To investigate the antibacterial effects of a crude extract of maggots against Escherichia coli(E.coli) and the underlying mechanisms,and to separate and purifythe crude extract of maggots to assess the antibacter...AIM:To investigate the antibacterial effects of a crude extract of maggots against Escherichia coli(E.coli) and the underlying mechanisms,and to separate and purifythe crude extract of maggots to assess the antibacterial effects of the active ingredients in the crude extract.METHODS:Different concentrations of the crude extract of maggots were incubated with E.coli(O157:H7) and cultured.The optical density(OD) was measured at different time points to plot the OD-T curve.The effects of different concentrations of the crude extract on bacterial membrane permeability were determined by fluorescence probe technique.The effects of different concentrations of the crude extract on plasmid DNA replication were determined by agarose gel electrophoresis.DEAE-Sepharose ion exchange chromatography and Sephacryls-200 HR gel filtration chromatography were used to separate and purify the crude extract of maggots.The molecular weight of proteins in the purified crude extract was determined by SDS-PAGD electrophoresis,and its antibacterial effects were determined by turbidimetric method.RESULTS:The antibacterial effects of the crude extract of maggots at concentrations > 0.5 mg/m L were significant.The antibacterial effects of the crude extract at concentrations of 1.0,1.5 and 2.0 mg/m L did not differ significantly.Fluorescence probe analysis showed that the rate of membrane permeability change was 1223.1% in bacteria incubated with 2 mg/m L of the crude extract,and 1300.0% in those incubated with 80 mg/m L of the crude extract.Plasmid DNA was undetectable in E.coli incubated with 2 and 80 mg/m L of the crude extract.A low molecular weight protein band(about 15 k Da) was detected in the crude extract of maggots and eluent,but not in eluant,from DEAE-Sepharose ion exchange chromatography.The antibacterial effects of the crude extract of maggots and eluent were superior to those of eluant,with the antibacterial effects of eluents being better than those of the crude extract of maggots.Of 24 tubes offiltrates,the antibacterial effects of filtrates in tubes 4,5 and 11 were significantly higher than those of the control.The molecular weight of the protein in filtrates in tubes 4,5 and 11 was about 15 k Da.CONCLUSION:The crude extract of maggots exhibits obvious,dose-dependent antibacterial effects.The crude extract exerts antibacterial effects by changing the bacterial membrane permeability and inhibiting plasmid DNA replication.The prote in that has antibacterial effects in the crude extract of maggots has a molecular weight of about 15 k Da.展开更多
It is very important to increase the quantum efficiency(QE)and prolong the lifetime of the photocathode in a variety of applications.We have succeeded in preparing a high QE cesium potassium antimonide(K-Cs-Sb)photoca...It is very important to increase the quantum efficiency(QE)and prolong the lifetime of the photocathode in a variety of applications.We have succeeded in preparing a high QE cesium potassium antimonide(K-Cs-Sb)photocathode by K and Cs co-evaporation in the photocathode preparation facility.In order to better understand the effect of the substrate(photocathode)temperature on the photocathode performance,the photocathode preparation,photocathode performance degradation,photocathode performance recovery and photocathode removal are studied in detail.展开更多
Proportioning is an important part of sintering,as it affects the cost of sintering and the quality of sintered ore.To address the problems posed by the complex raw material information and numerous constraints in the...Proportioning is an important part of sintering,as it affects the cost of sintering and the quality of sintered ore.To address the problems posed by the complex raw material information and numerous constraints in the sintering process,a multi-objective optimisation model for sintering proportioning was established,which takes the proportioning cost and TFe as the optimisation objectives.Additionally,an improved multi-objective beluga whale optimisation(IMOBWO)algorithm was proposed to solve the nonlinear,multi-constrained multi-objective optimisation problems.The algorithm uses the con-strained non-dominance criterion to deal with the constraint problem in the model.Moreover,the algorithm employs an opposite learning strategy and a population guidance mechanism based on angular competition and two-population competition strategy to enhance convergence and population diversity.The actual proportioning of a steel plant indicates that the IMOBWO algorithm applied to the ore proportioning process has good convergence and obtains the uniformly distributed Pareto front.Meanwhile,compared with the actual proportioning scheme,the proportioning cost is reduced by 4.3361¥/t,and the TFe content in the mixture is increased by 0.0367%in the optimal compromise solution.Therefore,the proposed method effectively balances the cost and total iron,facilitating the comprehensive utilisation of sintered iron ore resources while ensuring quality assurance.展开更多
A series of substituted para-, meta- and ortho-nitrophenyl derivatives of fulleropyrrolidine were synthesized to investigate the effects of the position of substitution on electronic properties by using steady-state a...A series of substituted para-, meta- and ortho-nitrophenyl derivatives of fulleropyrrolidine were synthesized to investigate the effects of the position of substitution on electronic properties by using steady-state absorption and fluorescence spectra, combined with DFT calculations. The results confirmed that the position of substitution has little effect on absorption and fluorescence spectra, whereas a significant effect was observed on their LUMO energy levels. The theoretical calculations revealed that the LUMO energy of the ortho-nitrophenyl substituted derivative was increased 0.1 eV above those ofpara- and meta-substitution. The prominent effect ofortho-substitution was attributed to the through-space orbital interaction between spatially closed electron-withdrawing nitro group and fullerene cage. These findings could provide fundamental insights in raising LUMO levels of C6o-based electron acceptor materials and an alternative strategy to increase open circuit voltage Voc in polymer solar cells.展开更多
Hyaluronic acid has been extensively investigated due to intrinsic properties of natural origin and strong ability to bind ions in water. Hyaluronic acid is an excellent crystal modifier because its abundant negativel...Hyaluronic acid has been extensively investigated due to intrinsic properties of natural origin and strong ability to bind ions in water. Hyaluronic acid is an excellent crystal modifier because its abundant negatively charged carboxyl groups can bind the cations protruding from the crystal lattice. In this review, we mainly present the latest work focus on the role of hyaluronic acid in controlling the crystallization, breaking the symmetry of crystal, and the surface funtionalization of nanocrystals.展开更多
The effects of various cooling paths on uniformity of through-thickness microstructure and mechanical properties of X80 pipeline steel of 22.0 mm in thickness were studied. The finite difference method was employed to...The effects of various cooling paths on uniformity of through-thickness microstructure and mechanical properties of X80 pipeline steel of 22.0 mm in thickness were studied. The finite difference method was employed to calculate the temperature field during cooling. It was confirmed by the experimental result and temperature field calculation that the optimizing process was achieved by the ultra-fast cooling with medium cooling capacity(cooling rate of *23 K/s)followed by ultimate cooling capacity(cooling rate of *50 K/s). After optimization, the experimental steel displayed much uniform microstructure and the deviation of through-thickness hardness was controlled within 20 HV. In addition,the yield strength, tensile strength and elongation of the experimental steel were 621, 728 MPa and 21.5%, respectively,meeting the requirements of the API standard for X80 pipeline steels.展开更多
Surface mechanical attrition treatment(SMAT) was carried out on hot-rolled AZ31 Mg samples along two orthogonal directions;as a result,two types of gradient structures with different grain sizes and texture components...Surface mechanical attrition treatment(SMAT) was carried out on hot-rolled AZ31 Mg samples along two orthogonal directions;as a result,two types of gradient structures with different grain sizes and texture components in different layers were produced.The tension-compression yield asymmetry(YA) was studied using samples with different thicknesses,in order to elucidate the effect of combinations of variable deformation modes operating in different layers of the two oriented SMAT samples.The 0° oriented SMAT sample containing layers with strong basal texture displayed significant YA,because of either dislocation slip or extension twinning domination during tension or compression.By contrast,the 90° oriented SMAT sample containing layers with coexisting orthogonal texture components had an obviously weakened YA,which was attributed to the multi-deformation modes cooperating during tension or compression,i.e.,extension twinning or detwinning in conjunction with dislocation slips,leading to close yield stresses compared between tension and compression.展开更多
A facile approach for constructing diverse architectures of unmodified C60 was developed via simple evaporation of pure C60 solution in CS2 under various poor solvent atmospheres. Diverse architectures such as belts, ...A facile approach for constructing diverse architectures of unmodified C60 was developed via simple evaporation of pure C60 solution in CS2 under various poor solvent atmospheres. Diverse architectures such as belts, sheets, and starfishes were successfully constructed under different experimental conditions. C60 belts obtained under EtOH atmosphere were confirmed to be a face-centered cubic (fcc) structure. The solvent atmospheres not only slowed clown the evaporation speed, but also could reorganize the self-assembly of C60 by partially re-dissolving the initially formed architectures. This concept represents a novel method for preparation of nanostructures of C60 and could also be applied for controlling of the self-assembly of other functional organic molecules.展开更多
In this paper,we provide some gentle introductions to the recent advance in augmented Lagrangian methods for solving large-scale convex matrix optimization problems(cMOP).Specifically,we reviewed two types of sufficie...In this paper,we provide some gentle introductions to the recent advance in augmented Lagrangian methods for solving large-scale convex matrix optimization problems(cMOP).Specifically,we reviewed two types of sufficient conditions for ensuring the quadratic growth conditions of a class of constrained convex matrix optimization problems regularized by nonsmooth spectral functions.Under a mild quadratic growth condition on the dual of cMOP,we further discussed the R-superlinear convergence of the Karush-Kuhn-Tucker(KKT)residuals of the sequence generated by the augmented Lagrangian methods(ALM)for solving convex matrix optimization problems.Implementation details of the ALM for solving core convex matrix optimization problems are also provided.展开更多
High-entropy alloys(HEAs)exhibit unique microstructural features and properties in nanoscale and atomic scale because of their multi-element alloy system.The nanoscratching behaviors of three HEAs with different phase...High-entropy alloys(HEAs)exhibit unique microstructural features and properties in nanoscale and atomic scale because of their multi-element alloy system.The nanoscratching behaviors of three HEAs with different phase constituents,relative to the microstructure and mechanical properties of the HEAs,were investigated.Three typical phase constituents were selected:face-centered cubic(FCC)structure,body-centered cubic(BCC)structure,and a dual-phase structure containing both FCC and BCC phases.Despite the fact that the FCC alloy has the highest ductility and strain hardening capability,it exhibited inferior scratch resistance due to the over-softening of hardness.Due to the brittle failure mode,the BCC alloy hardly exhibited desirable scratch resistance despite its highest hardness.By contrast,the nanostructured dual-phase alloy exhibited the best scratch resistance because of its good combination of strength and ductility,as well as the ductile failure mode.This research suggests that the HEA with structure comprising nanoscale hard and soft phases is desirable for nanoscratch resistance,and possesses appropriate hardness for industrial applications.展开更多
基金the State Key Laboratory of Pathogen and Biosecurity,No.SKLPBS2119 and SKLPBS2212the Medical Science Research Project of Dalian,No.2112015。
文摘BACKGROUND Formyl peptide receptor 2(Fpr2)is an important receptor in host resistance to bacterial infections.In previous studies,we found that the liver of Fpr2-/-mice is the most severely damaged target organ in bloodstream infections,although the reason for this is unclear.AIM To investigate the role of Fpr2 in liver homeostasis and host resistance to bacterial infections.METHODS Transcriptome sequencing was performed on the livers of Fpr2-/-and wild-type(WT)mice.Differentially expressed genes(DEGs)were identified in the Fpr2-/-and WT mice,and the biological functions of DEGs were analyzed by Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis.Quantitative real time-polymerase chain reaction(qRT-PCR)and western blot(WB)analyses were used to further validate the expression levels of differential genes.Cell counting kit-8 assay was employed to investigate cell survival.The cell cycle detection kit was used to measure the distribution of cell cycles.The Luminex assay was used to analyze cytokine levels in the liver.The serum biochemical indices and the number of neutrophils in the liver were measured,and hepatic histopathological analysis was performed.RESULTS Compared with the WT group,445 DEGs,including 325 upregulated genes and 120 downregulated genes,were identified in the liver of Fpr2-/-mice.The enrichment analysis using GO and KEGG showed that these DEGs were mainly related to cell cycle.The qRT-PCR analysis confirmed that several key genes(CycA,CycB1,Cdc20,Cdc25c,and Cdk1)involved in the cell cycle had significant changes.The WB analysis confirmed a decrease in the expression of CDK1 protein.WRW4(an antagonist of Fpr2)could inhibit the proliferation of HepG2 cells in a concentration dependent manner,with an increase in the number of cells in the G0/G1 phase,and a decrease in the number of cells in the S phase.Serum alanine aminotransferase levels increased in Fpr2-/-mice.The Luminex assay measurements showed that interleukin(IL)-10 and chemokine(C-X-C motif)ligand(CXCL)-1 levels were significantly reduced in the liver of Fpr2-/-mice.There was no difference in the number of neutrophils,serum C-reactive protein levels,and liver pathology between WT and Fpr2-/-mice.CONCLUSION Fpr2 participates in the regulation of cell cycle and cell proliferation,and affects the expression of IL-10 and CXCL-1,thus playing an important protective role in maintaining liver homeostasis.
基金Supported by National Natural Science Foundation of China,No.81270052
文摘AIM:To investigate the antibacterial effects of a crude extract of maggots against Escherichia coli(E.coli) and the underlying mechanisms,and to separate and purifythe crude extract of maggots to assess the antibacterial effects of the active ingredients in the crude extract.METHODS:Different concentrations of the crude extract of maggots were incubated with E.coli(O157:H7) and cultured.The optical density(OD) was measured at different time points to plot the OD-T curve.The effects of different concentrations of the crude extract on bacterial membrane permeability were determined by fluorescence probe technique.The effects of different concentrations of the crude extract on plasmid DNA replication were determined by agarose gel electrophoresis.DEAE-Sepharose ion exchange chromatography and Sephacryls-200 HR gel filtration chromatography were used to separate and purify the crude extract of maggots.The molecular weight of proteins in the purified crude extract was determined by SDS-PAGD electrophoresis,and its antibacterial effects were determined by turbidimetric method.RESULTS:The antibacterial effects of the crude extract of maggots at concentrations > 0.5 mg/m L were significant.The antibacterial effects of the crude extract at concentrations of 1.0,1.5 and 2.0 mg/m L did not differ significantly.Fluorescence probe analysis showed that the rate of membrane permeability change was 1223.1% in bacteria incubated with 2 mg/m L of the crude extract,and 1300.0% in those incubated with 80 mg/m L of the crude extract.Plasmid DNA was undetectable in E.coli incubated with 2 and 80 mg/m L of the crude extract.A low molecular weight protein band(about 15 k Da) was detected in the crude extract of maggots and eluent,but not in eluant,from DEAE-Sepharose ion exchange chromatography.The antibacterial effects of the crude extract of maggots and eluent were superior to those of eluant,with the antibacterial effects of eluents being better than those of the crude extract of maggots.Of 24 tubes offiltrates,the antibacterial effects of filtrates in tubes 4,5 and 11 were significantly higher than those of the control.The molecular weight of the protein in filtrates in tubes 4,5 and 11 was about 15 k Da.CONCLUSION:The crude extract of maggots exhibits obvious,dose-dependent antibacterial effects.The crude extract exerts antibacterial effects by changing the bacterial membrane permeability and inhibiting plasmid DNA replication.The prote in that has antibacterial effects in the crude extract of maggots has a molecular weight of about 15 k Da.
基金the National Natural Science Foundation of China under Grant No.11405251the Shanghai Municipal Science and Technology Major Project.
文摘It is very important to increase the quantum efficiency(QE)and prolong the lifetime of the photocathode in a variety of applications.We have succeeded in preparing a high QE cesium potassium antimonide(K-Cs-Sb)photocathode by K and Cs co-evaporation in the photocathode preparation facility.In order to better understand the effect of the substrate(photocathode)temperature on the photocathode performance,the photocathode preparation,photocathode performance degradation,photocathode performance recovery and photocathode removal are studied in detail.
基金supported by the National Key Research and Development Program of China (2022YFB3304700)Hunan Province Natural Science Foundation (2022JJ50132,2022JCYJ05 and 2022JCYJ09).
文摘Proportioning is an important part of sintering,as it affects the cost of sintering and the quality of sintered ore.To address the problems posed by the complex raw material information and numerous constraints in the sintering process,a multi-objective optimisation model for sintering proportioning was established,which takes the proportioning cost and TFe as the optimisation objectives.Additionally,an improved multi-objective beluga whale optimisation(IMOBWO)algorithm was proposed to solve the nonlinear,multi-constrained multi-objective optimisation problems.The algorithm uses the con-strained non-dominance criterion to deal with the constraint problem in the model.Moreover,the algorithm employs an opposite learning strategy and a population guidance mechanism based on angular competition and two-population competition strategy to enhance convergence and population diversity.The actual proportioning of a steel plant indicates that the IMOBWO algorithm applied to the ore proportioning process has good convergence and obtains the uniformly distributed Pareto front.Meanwhile,compared with the actual proportioning scheme,the proportioning cost is reduced by 4.3361¥/t,and the TFe content in the mixture is increased by 0.0367%in the optimal compromise solution.Therefore,the proposed method effectively balances the cost and total iron,facilitating the comprehensive utilisation of sintered iron ore resources while ensuring quality assurance.
基金supported by Shanghai Pujiang Program(No.11PJ1400200)Innovation Program of Shanghai Municipal Education Commission(No.12ZZ067)+1 种基金the Research Fund for the Doctoral Program of Higher Education of Chinathe Fundamental Research Funds for the Central Universities
文摘A series of substituted para-, meta- and ortho-nitrophenyl derivatives of fulleropyrrolidine were synthesized to investigate the effects of the position of substitution on electronic properties by using steady-state absorption and fluorescence spectra, combined with DFT calculations. The results confirmed that the position of substitution has little effect on absorption and fluorescence spectra, whereas a significant effect was observed on their LUMO energy levels. The theoretical calculations revealed that the LUMO energy of the ortho-nitrophenyl substituted derivative was increased 0.1 eV above those ofpara- and meta-substitution. The prominent effect ofortho-substitution was attributed to the through-space orbital interaction between spatially closed electron-withdrawing nitro group and fullerene cage. These findings could provide fundamental insights in raising LUMO levels of C6o-based electron acceptor materials and an alternative strategy to increase open circuit voltage Voc in polymer solar cells.
文摘Hyaluronic acid has been extensively investigated due to intrinsic properties of natural origin and strong ability to bind ions in water. Hyaluronic acid is an excellent crystal modifier because its abundant negatively charged carboxyl groups can bind the cations protruding from the crystal lattice. In this review, we mainly present the latest work focus on the role of hyaluronic acid in controlling the crystallization, breaking the symmetry of crystal, and the surface funtionalization of nanocrystals.
基金supported by the National Natural Science Foundation of China(No.51234002)the Fundamental Research Funds for the Central Universities(N130407001)
文摘The effects of various cooling paths on uniformity of through-thickness microstructure and mechanical properties of X80 pipeline steel of 22.0 mm in thickness were studied. The finite difference method was employed to calculate the temperature field during cooling. It was confirmed by the experimental result and temperature field calculation that the optimizing process was achieved by the ultra-fast cooling with medium cooling capacity(cooling rate of *23 K/s)followed by ultimate cooling capacity(cooling rate of *50 K/s). After optimization, the experimental steel displayed much uniform microstructure and the deviation of through-thickness hardness was controlled within 20 HV. In addition,the yield strength, tensile strength and elongation of the experimental steel were 621, 728 MPa and 21.5%, respectively,meeting the requirements of the API standard for X80 pipeline steels.
基金financially suppor ted by the Defense Industrial Technology Development Program(No.JCKY2018407C008)the National Natural Science Foundation of China(NSFC)(No.51304061)the NCST Science Fund for Distinguished Young Scholars(No.JQ201702).
文摘Surface mechanical attrition treatment(SMAT) was carried out on hot-rolled AZ31 Mg samples along two orthogonal directions;as a result,two types of gradient structures with different grain sizes and texture components in different layers were produced.The tension-compression yield asymmetry(YA) was studied using samples with different thicknesses,in order to elucidate the effect of combinations of variable deformation modes operating in different layers of the two oriented SMAT samples.The 0° oriented SMAT sample containing layers with strong basal texture displayed significant YA,because of either dislocation slip or extension twinning domination during tension or compression.By contrast,the 90° oriented SMAT sample containing layers with coexisting orthogonal texture components had an obviously weakened YA,which was attributed to the multi-deformation modes cooperating during tension or compression,i.e.,extension twinning or detwinning in conjunction with dislocation slips,leading to close yield stresses compared between tension and compression.
基金supported by the National Natural Science Foundation of China(Nos.81171472,81201407,and 81071270)the Innovation Team Project of Sichuan Provincial Education Department(No.13TD0030)+1 种基金the Major Transformation Cultivation Project of Sichuan Provincial Education Department(No.15CZ0021)the Science and Technology Project of Nanchong City(No.14A0021),China
基金supported by the Innovation Program of Shanghai Municipal Education Commission(No.12ZZ067)Shanghai Pujiang Program(No.11PJ1400200)+1 种基金the Research Fund for the Doctoral Program of Higher Education of China(No.20120075120018)the Fundamental Research Funds for the Central Universities
文摘A facile approach for constructing diverse architectures of unmodified C60 was developed via simple evaporation of pure C60 solution in CS2 under various poor solvent atmospheres. Diverse architectures such as belts, sheets, and starfishes were successfully constructed under different experimental conditions. C60 belts obtained under EtOH atmosphere were confirmed to be a face-centered cubic (fcc) structure. The solvent atmospheres not only slowed clown the evaporation speed, but also could reorganize the self-assembly of C60 by partially re-dissolving the initially formed architectures. This concept represents a novel method for preparation of nanostructures of C60 and could also be applied for controlling of the self-assembly of other functional organic molecules.
基金Chao Ding’s research was supported by the National Natural Science Foundation of China(Nos.11671387,11531014,and 11688101)Beijing Natural Science Foundation(No.Z190002)+6 种基金Xu-Dong Li’s research was supported by the National Key R&D Program of China(No.2020YFA0711900)the National Natural Science Foundation of China(No.11901107)the Young Elite Scientists Sponsorship Program by CAST(No.2019QNRC001)the Shanghai Sailing Program(No.19YF1402600)the Science and Technology Commission of Shanghai Municipality Project(No.19511120700)Xin-Yuan Zhao’s research was supported by the National Natural Science Foundation of China(No.11871002)the General Program of Science and Technology of Beijing Municipal Education Commission(No.KM201810005004).
文摘In this paper,we provide some gentle introductions to the recent advance in augmented Lagrangian methods for solving large-scale convex matrix optimization problems(cMOP).Specifically,we reviewed two types of sufficient conditions for ensuring the quadratic growth conditions of a class of constrained convex matrix optimization problems regularized by nonsmooth spectral functions.Under a mild quadratic growth condition on the dual of cMOP,we further discussed the R-superlinear convergence of the Karush-Kuhn-Tucker(KKT)residuals of the sequence generated by the augmented Lagrangian methods(ALM)for solving convex matrix optimization problems.Implementation details of the ALM for solving core convex matrix optimization problems are also provided.
基金The authors are grateful for the financial supports from the Defense Industrial Technology Development Program(No.JCKY2018407C008)the National Natural Science Foundation of China(NSFC)(Grant Nos.51304061 and 51474092)the NCST Science Fund for Distinguished Young Scholars(No.JQ201702).
文摘High-entropy alloys(HEAs)exhibit unique microstructural features and properties in nanoscale and atomic scale because of their multi-element alloy system.The nanoscratching behaviors of three HEAs with different phase constituents,relative to the microstructure and mechanical properties of the HEAs,were investigated.Three typical phase constituents were selected:face-centered cubic(FCC)structure,body-centered cubic(BCC)structure,and a dual-phase structure containing both FCC and BCC phases.Despite the fact that the FCC alloy has the highest ductility and strain hardening capability,it exhibited inferior scratch resistance due to the over-softening of hardness.Due to the brittle failure mode,the BCC alloy hardly exhibited desirable scratch resistance despite its highest hardness.By contrast,the nanostructured dual-phase alloy exhibited the best scratch resistance because of its good combination of strength and ductility,as well as the ductile failure mode.This research suggests that the HEA with structure comprising nanoscale hard and soft phases is desirable for nanoscratch resistance,and possesses appropriate hardness for industrial applications.