Considering the expansion of mining operations into increasingly deeper areas,it is imperative to assess the influence of dynamic disturbance loads on the security of deep tunnels.Here,via AUTODYN finite difference so...Considering the expansion of mining operations into increasingly deeper areas,it is imperative to assess the influence of dynamic disturbance loads on the security of deep tunnels.Here,via AUTODYN finite difference software,a numerical analysis of the fracture characteristics of a fractured tunnel was employed under the coupled action of in-situ stress and dynamic disturbance loads.The experimental setup comprised a tunnel model with“I-shaped”cracks,and a drop impact device(DID)was employed to generate dynamic wave loads.A crack fracture test(CFT)was utilized to gather information on the fracture process,including initiation time and average propagation rate.A series of combined scenarios were subsequently simulated to replicate various in situ stress levels(ranging from 0.5 to 2.5 MPa)and dynamic loads.The results indicate that with increasing in situ stress,the crack propagation rate,crack propagation length,and crack break time(CBT)decrease;moreover,the circumferential tensile stress concentration factor in the tunnel also decreases,enhancing tunnel stability.Finally,changes in ground stress influence the propagation path of cracks.展开更多
There are many achievements in the field of analytical mechanics, such as Lagrange Equation, Hamilton’s Principle, Kane’s Equation. Compared to Newton–Euler mechanics, analytical mechanics have a wider range of app...There are many achievements in the field of analytical mechanics, such as Lagrange Equation, Hamilton’s Principle, Kane’s Equation. Compared to Newton–Euler mechanics, analytical mechanics have a wider range of applications and the formulation procedures are more mathematical. However, all existing methods of analytical mechanics were proposed based on some auxiliary variables. In this review, a novel analytical mechanics approach without the aid of Lagrange’s multiplier, projection, or any quasi or auxiliary variables is introduced for the central problem of mechanical systems. Since this approach was firstly proposed by Udwadia and Kalaba, it was called Udwadia–Kalaba Equation. It is a representation for the explicit expression of the equations of motion for constrained mechanical systems. It can be derived via the Gauss’ s principle, d’Alembert’s principle or extended d’Alembert’s principle. It is applicable to both holonomic and nonholonomic equality constraints, as long as they are linear with respect to the accelerations or reducible to be that form. As a result, the Udwadia–Kalaba Equation can be applied to a very broad class of mechani?cal systems. This review starts with introducing the background by a brief review of the history of mechanics. After that, the formulation procedure of Udwadia–Kalaba Equation is given. Furthermore, the comparisons of Udwadia–Kalaba Equation with Newton–Euler Equation, Lagrange Equation and Kane’s Equation are made, respectively. At last, three di erent types of examples are given for demonstrations.展开更多
Hepatocellular carcinoma(HCC)is a worldwide malignant tumor that caused irreversible consequences.Tanshinone IIA has been shown to play a notable role in HCC treatment.However,the potential targets and associating mec...Hepatocellular carcinoma(HCC)is a worldwide malignant tumor that caused irreversible consequences.Tanshinone IIA has been shown to play a notable role in HCC treatment.However,the potential targets and associating mechanism of Tanshinone IIA against HCC remain unknown.We first screened out 105 overlapping genes by integrating the predicted targets of Tanshinone IIA from multiple databases and the differentially expressed genes of HCC from the Cancer Genome Atlas(TCGA)database.Then,we performed weighted gene co-expression network analysis(WGCNA)using the RNA-seq profiles of overlapping genes and HCC-related clinical information.23 genes related to clinical tumor grade in the important module were imported for Gene Ontology(GO)enrichment,Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis and protein-protein interaction(PPI)analysis.Comparing the key genes in the important module from WGCNA with the high connectivity nodes from the PPI network,we identified three hub genes,AURKB,KIF11,and PLK1.For further verification,we tested the binding of Tanshinone IIA to three hub genes.The survival curve,receiver operating characteristic(ROC)curve,mRNA expression,and protein expression were also used to validate the hub genes.In the study,WGCNA revealed gradespecific gene modules,and the following KEGG pathway analysis indicated that Tanshinone IIA probably plays therapeutical effect in the development of HCC,especially in the cell cycle.Our result partially explained the pharmacological mechanism of Tanshinone IIA against HCC.展开更多
Columnar grains offer considerable advantages in terms of microstructure for resisting high-temperature low-cycle fatigue. In additive manufacturing, the formation of fine columnar grains is common. However, post-heat...Columnar grains offer considerable advantages in terms of microstructure for resisting high-temperature low-cycle fatigue. In additive manufacturing, the formation of fine columnar grains is common. However, post-heat treatment often transforms these grains into equiaxed grains. This study aimed to tailor the grain morphology by controlling the precipitation of carbides. By balancing the restraining effects of carbide pinning and grain growth, we achieved carbide-assisted in situ-directional recrystallization. This process preserved the columnar grains created via laser powder bed fusion, even after high-temperature heat treatment. The approach emphasizes promoting the longitudinal growth of columnar grains while preventing their broadening. Additionally, we characterized the evolution of carbides and γ′ precipitates and examined their role in nucleation and growth during recrystallization. This study supports the viability of carbide-assisted in situ-directional recrystallization in additive manufacturing alloys, introducing an innovative strategy for microstructure customization. The implementation of carbon stabilization (CS) treatment to control the carbide distribution led to a 40 % improvement in the creep life at 900 ℃ and 150 MPa.展开更多
基金Research Development Fund of Zhejiang A&F University,Grant/Award Number:2023LFR026National Natural Science Foundation of China,Grant/Award Numbers:12272247,52078467,52204104,52478371+1 种基金Sichuan Science and Technology Program,Grant/Award Numbers:2023NSFSC0908,2024YFHZ0033National Science Foundation of Zhejiang Province,Grant/Award Number:LHZ21E09001。
文摘Considering the expansion of mining operations into increasingly deeper areas,it is imperative to assess the influence of dynamic disturbance loads on the security of deep tunnels.Here,via AUTODYN finite difference software,a numerical analysis of the fracture characteristics of a fractured tunnel was employed under the coupled action of in-situ stress and dynamic disturbance loads.The experimental setup comprised a tunnel model with“I-shaped”cracks,and a drop impact device(DID)was employed to generate dynamic wave loads.A crack fracture test(CFT)was utilized to gather information on the fracture process,including initiation time and average propagation rate.A series of combined scenarios were subsequently simulated to replicate various in situ stress levels(ranging from 0.5 to 2.5 MPa)and dynamic loads.The results indicate that with increasing in situ stress,the crack propagation rate,crack propagation length,and crack break time(CBT)decrease;moreover,the circumferential tensile stress concentration factor in the tunnel also decreases,enhancing tunnel stability.Finally,changes in ground stress influence the propagation path of cracks.
基金Supported by National Natural Science Foundation of China(Grant No.51705116)Anhui Provincial Science and Technology Major Project of China(Grant No.17030901036)Fundamental Research Funds for the Central Universities of China(Grant Nos.JZ2018HGBZ0096,JZ2018HGTA0217,JZ2018HGTB0261)
文摘There are many achievements in the field of analytical mechanics, such as Lagrange Equation, Hamilton’s Principle, Kane’s Equation. Compared to Newton–Euler mechanics, analytical mechanics have a wider range of applications and the formulation procedures are more mathematical. However, all existing methods of analytical mechanics were proposed based on some auxiliary variables. In this review, a novel analytical mechanics approach without the aid of Lagrange’s multiplier, projection, or any quasi or auxiliary variables is introduced for the central problem of mechanical systems. Since this approach was firstly proposed by Udwadia and Kalaba, it was called Udwadia–Kalaba Equation. It is a representation for the explicit expression of the equations of motion for constrained mechanical systems. It can be derived via the Gauss’ s principle, d’Alembert’s principle or extended d’Alembert’s principle. It is applicable to both holonomic and nonholonomic equality constraints, as long as they are linear with respect to the accelerations or reducible to be that form. As a result, the Udwadia–Kalaba Equation can be applied to a very broad class of mechani?cal systems. This review starts with introducing the background by a brief review of the history of mechanics. After that, the formulation procedure of Udwadia–Kalaba Equation is given. Furthermore, the comparisons of Udwadia–Kalaba Equation with Newton–Euler Equation, Lagrange Equation and Kane’s Equation are made, respectively. At last, three di erent types of examples are given for demonstrations.
基金This study was supported by Health Commission of Hubei Province Scientific Research Project[WJ2021M217]the Scientific Research Program of Jianghan University(2021yb131)the Scientific Research foundation of Jianghan University(No.2020010).
文摘Hepatocellular carcinoma(HCC)is a worldwide malignant tumor that caused irreversible consequences.Tanshinone IIA has been shown to play a notable role in HCC treatment.However,the potential targets and associating mechanism of Tanshinone IIA against HCC remain unknown.We first screened out 105 overlapping genes by integrating the predicted targets of Tanshinone IIA from multiple databases and the differentially expressed genes of HCC from the Cancer Genome Atlas(TCGA)database.Then,we performed weighted gene co-expression network analysis(WGCNA)using the RNA-seq profiles of overlapping genes and HCC-related clinical information.23 genes related to clinical tumor grade in the important module were imported for Gene Ontology(GO)enrichment,Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis and protein-protein interaction(PPI)analysis.Comparing the key genes in the important module from WGCNA with the high connectivity nodes from the PPI network,we identified three hub genes,AURKB,KIF11,and PLK1.For further verification,we tested the binding of Tanshinone IIA to three hub genes.The survival curve,receiver operating characteristic(ROC)curve,mRNA expression,and protein expression were also used to validate the hub genes.In the study,WGCNA revealed gradespecific gene modules,and the following KEGG pathway analysis indicated that Tanshinone IIA probably plays therapeutical effect in the development of HCC,especially in the cell cycle.Our result partially explained the pharmacological mechanism of Tanshinone IIA against HCC.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFA0705300)the National Natural Science Foundation of China(Grant No.51974057)the Fundamental Research Funds for the Central Universities。
文摘Columnar grains offer considerable advantages in terms of microstructure for resisting high-temperature low-cycle fatigue. In additive manufacturing, the formation of fine columnar grains is common. However, post-heat treatment often transforms these grains into equiaxed grains. This study aimed to tailor the grain morphology by controlling the precipitation of carbides. By balancing the restraining effects of carbide pinning and grain growth, we achieved carbide-assisted in situ-directional recrystallization. This process preserved the columnar grains created via laser powder bed fusion, even after high-temperature heat treatment. The approach emphasizes promoting the longitudinal growth of columnar grains while preventing their broadening. Additionally, we characterized the evolution of carbides and γ′ precipitates and examined their role in nucleation and growth during recrystallization. This study supports the viability of carbide-assisted in situ-directional recrystallization in additive manufacturing alloys, introducing an innovative strategy for microstructure customization. The implementation of carbon stabilization (CS) treatment to control the carbide distribution led to a 40 % improvement in the creep life at 900 ℃ and 150 MPa.
