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In this paper, a numerical simulation method based on the camshaft casting process and crack expansion was proposed to study the propagation characteristics of casting hot cracks. The dynamic visualisation process of hot crack growth indicates that the formation of hot tear is dominated by opening mode cracks. And during the propagation process, the equivalent stress intensity factor at the crack front first decreases and then increases. Furthermore, the propagation characteristics of the crack under different hot tear initiation conditions were studied by this method. The results reveal that the expansion ability of a hot crack is affected by the equilibrium solidification scale, solidification sequence, and solidification path of the casting. Finally, using the microscopic morphology of the cracks, the semi-quantitative analysis of the elements illustrates that the carbon content decreases sharply at the crack formation site, while manganese and sulphur are relatively rich. [ABSTRACT FROM AUTHOR]

Phoebe minutiflora H. W. Li, is a member of the Lauraceae family, while its generic relationship has been long-term controversial. The complete chloroplast (cp) genome of P. minutiflora was first reported in this paper. The cp genome was 152,654 bp in length with four typical quadripartite structures, which was consisted of a large single-copy (LSC) region of 93,697 bp, a small single-copy (SSC) region of 18,809 bp, and two inverted repeats (IRs) of 20,074 bp. In addition, there were a total of 112 unique genes, including 79 protein-coding genes, 29 tRNA genes, and four rRNA genes. The phylogenetic analysis indicated that P. minutiflora should be placed into Machilus. [ABSTRACT FROM AUTHOR]