Objective:This work aimed to report the first complete mitochondrial genome(mitogenome)of Rheum palmatum,summarize the features of Caryophyllales mitogenomes,and to reveal the potential of utilizing the mitogenomes of...Objective:This work aimed to report the first complete mitochondrial genome(mitogenome)of Rheum palmatum,summarize the features of Caryophyllales mitogenomes,and to reveal the potential of utilizing the mitogenomes of R.palmatum and other Caryophyllales species for inferring phylogenetic relationships and species identification.Methods:Both Illumina short reads and PacBio HiFi reads were utilized to obtain a complete mitogenome of R.palmatum.A variety of bioinformatics tools were employed to characterize the R.palmatum mitogenome,compare the reported mitogenomes in Caryophyllales and conduct phylogenetic analysis.Results:The mitogenome of R.palmatum was assembled into a single master circle of 302,993 bp,encoding 35 known protein-coding genes,18 transfer RNA genes,and three ribosome RNA genes.A total of 249 long repeats and 49 simple sequence repeats were identified in this mitogenome.The sizes of mitogenomes in Caryophyllales varied from 253 kb to 11.3 Mb.Among them,23 mitogenomes were circular molecules,one was linear,and one consisted of relaxed circles,linear molecules,and supercoiled DNA.Out of the total mitogenomes,11 were single-chromosome structure,whereas the remaining 14 were multi-chromosomal organizations.The phylogenetic analysis is consistent with both the Engler system(1964)and the Angiosperm Phylogeny Group III system.Conclusions:We obtained the first mitogenome of R.palmatum,which consists of a master circle.Mitogenomes in Caryophyllales have variable genome sizes and structures even within the same species.Circular molecules are still the dominant pattern in Caryophyllales.Single-chromosome mitogenomes account for nearly a half of all the mitogenomes in Caryophyllales,in contrast to previous studies.It is feasible to utilize mitochondrial genomes for inferring phylogenetic relationships and conducting species identification.展开更多
This study is concerned with the instability analysis and improvement of a high-pressure and highflow air pressure-reducing regulator(HPHFPRR).The outlet pressure of HPHFPRR abruptly exceeds the initial set pressure v...This study is concerned with the instability analysis and improvement of a high-pressure and highflow air pressure-reducing regulator(HPHFPRR).The outlet pressure of HPHFPRR abruptly exceeds the initial set pressure value under high-pressure and high-flow conditions.To address this instability issue of HPHFPRR during practical usage,this study conducted simulations to analyze the transient flow field characteristics under varying valve opening degrees,unlike most studies that focused on unsteady turbulent behaviors at fixed valve openings.The investigation examined variations in the internal flow field and air force acting on the valve spool at different degrees of valve opening for HPHFPRR.Moreover,a dynamic model was established to deeply analyze the motion process and forces experienced by the valve spool and piston in HPHFPRR,and an optimized spool structure was experimentally verified.Results demonstrated that the gas flow force acting on the valve spool was responsible for sudden outlet pressure rise in HPHFPRR.After design optimizations,the maximum gas flow force on the newly designed valve spool decreased by 32.7%during HPHFPRR opening,effectively resolving abnormal instability issues under high-pressure conditions encountered in projects.展开更多
基金financially supported by the National Natural Science Foundation of China (81874339)Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences (2022-I2M-1-018).
文摘Objective:This work aimed to report the first complete mitochondrial genome(mitogenome)of Rheum palmatum,summarize the features of Caryophyllales mitogenomes,and to reveal the potential of utilizing the mitogenomes of R.palmatum and other Caryophyllales species for inferring phylogenetic relationships and species identification.Methods:Both Illumina short reads and PacBio HiFi reads were utilized to obtain a complete mitogenome of R.palmatum.A variety of bioinformatics tools were employed to characterize the R.palmatum mitogenome,compare the reported mitogenomes in Caryophyllales and conduct phylogenetic analysis.Results:The mitogenome of R.palmatum was assembled into a single master circle of 302,993 bp,encoding 35 known protein-coding genes,18 transfer RNA genes,and three ribosome RNA genes.A total of 249 long repeats and 49 simple sequence repeats were identified in this mitogenome.The sizes of mitogenomes in Caryophyllales varied from 253 kb to 11.3 Mb.Among them,23 mitogenomes were circular molecules,one was linear,and one consisted of relaxed circles,linear molecules,and supercoiled DNA.Out of the total mitogenomes,11 were single-chromosome structure,whereas the remaining 14 were multi-chromosomal organizations.The phylogenetic analysis is consistent with both the Engler system(1964)and the Angiosperm Phylogeny Group III system.Conclusions:We obtained the first mitogenome of R.palmatum,which consists of a master circle.Mitogenomes in Caryophyllales have variable genome sizes and structures even within the same species.Circular molecules are still the dominant pattern in Caryophyllales.Single-chromosome mitogenomes account for nearly a half of all the mitogenomes in Caryophyllales,in contrast to previous studies.It is feasible to utilize mitochondrial genomes for inferring phylogenetic relationships and conducting species identification.
基金supported by the National Natural Science Foundation of China(Grant No.51705164).
文摘This study is concerned with the instability analysis and improvement of a high-pressure and highflow air pressure-reducing regulator(HPHFPRR).The outlet pressure of HPHFPRR abruptly exceeds the initial set pressure value under high-pressure and high-flow conditions.To address this instability issue of HPHFPRR during practical usage,this study conducted simulations to analyze the transient flow field characteristics under varying valve opening degrees,unlike most studies that focused on unsteady turbulent behaviors at fixed valve openings.The investigation examined variations in the internal flow field and air force acting on the valve spool at different degrees of valve opening for HPHFPRR.Moreover,a dynamic model was established to deeply analyze the motion process and forces experienced by the valve spool and piston in HPHFPRR,and an optimized spool structure was experimentally verified.Results demonstrated that the gas flow force acting on the valve spool was responsible for sudden outlet pressure rise in HPHFPRR.After design optimizations,the maximum gas flow force on the newly designed valve spool decreased by 32.7%during HPHFPRR opening,effectively resolving abnormal instability issues under high-pressure conditions encountered in projects.
