Subjects: Biology >> Botany >> Applied botany submitted time 2024-04-17 Cooperative journals: 《广西植物》
Abstract： The classification of Mussaenda L. has been controversial due to the complex interspecific variation and hybridization within the genus, by exploring the variation patterns and taxonomical significance of the leaf venation characteristics between Mussaenda L. and its relative genera (Schizomussaenda Li and Psudomussaenda Wernham.), it could be provide data for the identification and utilization when they were regarded as the medical and garden plant resources. The leaf venation characteristics of 22 species of this group were observed by using the cleaning method. The cluster analysis was carried out based on the characteristics of leaf venation, and a classification retrieval table of the species was compiled. The results were as follows: (1) The characteristics of the leaf venation of Mussaenda L. and its relative genera had consistency, which were mainly reflected on that the primary veins were all pinnate, the frequency of intersecondary veins was less than one per areolation, the angle between the major secondary veins and the midvein was acute, the tertiary veins were mostly penetrating, and the arrangement of the areolation were all irregular. (2) The characteristics of the leaf venation with taxonomic value among genera or species within genera included the type of major secondary vein venation, the angle between the major secondary vein and the midvein, the spacing between the major secondary vein and the midvein, the connection between the major secondary vein and the midvein, the existence of inter-secondary veins and intramarginal secondary veins, the penetration of intercostal tertiary veins, the type of quaternary veins, the branching of freely ending veinlets, and the development of areolation. (3) According to the cluster analysis, the 22 species were clustered into 12 branches, and Schizomussaenda and Psudomussaenda were not clustered into one branch respectively, showing a relatively close genetic relationship. In conclusion, the leaf venation characteristics of Mussaenda and its related taxa can provide new information for the classification of the plants.
Subjects: Mechanics >> Applied Mechanics submitted time 2023-03-20 Cooperative journals: 《应用力学学报》
Abstract： In order to explore the feasibility of using desert sand entirely to prepare engineered cementi-tious composites (ECCs) in Xinjiang region , and study the uniaxial compression size effect of ECCs whichare prepared entirely from desert sand , on the basis of analyzing and comparing the macroscopic mechani-cal properties and microstructure of ECCs prepared by three aggregates ( i. e. , desert sand, quartz sand,and river sand) , the uniaxial compression tests of five groups of desert sand ECC specimens with differentsizes were carried out. The results show that at the same ratio of materials , the ECCs prepared entirely byusing desert sand have compressive , tensile , and flexural strength similar to that of the ECC prepared by the other two kinds of sand , in desert sand ECCs , fewer attachments and relatively complete morphology offiber surface are beneficial to its bridging effect;the uniaxial compression properties of ECC prepared en-tirely by using desert sand have size effect ; the expression of the relation between height-thickness ratioand compressive strength , and the stress-strain full curve model with dfferent height-thickness ratio are ingood agreement with the test results.
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