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Rhododendron is well‐known for its beauty and colourful corolla. Although some high‐quality whole‐genome sequencing of it has been completed, there are few studies on long terminal repeat (LTR) retrotransposons in Rhododendron, which limits our ability to elucidate the causes of genetic variations in Rhododendron species. Properties of the intact Rhododendron LTR retrotransposons were investigated at a genome‐wide level. Based on available data, the high‐quality genomes from five species, i.e. R. griersonianum, R. simsii, R. henanense subsp. lingbaoense, R. mucronatum var. ripense and R. ovatum, were selected as targets with good assembly continuity. A total of 17,936 intact LTR retrotransposons were identified; these belong to superfamilies Copia and Gypsy, with 17 clades. The insertion time of these transposons was later than 120 million years ago (Mya), and the outbreak period was concentrated more recently than 30 Mya. Phylogenetic analysis revealed that many LTR retrotransposons might originate from intraspecific duplication. Current evidence also suggests that most LTR retrotransposons were inserted in the interstitial part of genes in R. griersonianum, R. simsii, R. henanense, and R. ovatum, and the functions of the inserted genes mainly involve starch metabolism, proteolysis, etc. The effect of the LTR retrotransposon on gene expression depends on its insertion site and activation. Highly expressed LTR retrotransposons tend to be younger. The results herein improve our knowledge of LTR retrotransposons in Rhododendron genomes and facilitate further study of genetic variation and trait evolution in Rhododendron.

The interfacial heat transfer coefficient (IHTC) is a critical thermophysical parameter indicating the ability of heat transfer between different bodies. In this paper, an advanced temperature acquisition system was established based on direct measurement, a theoretical model of interfacial heat transfer and an inverse algorithm of the IHTC was developed. Besides, the influence of contact pressure and martensitic transformation on IHTC of coated boron steel (Usibor 1500P) and uncoated boron steel (B1500HS) were investigated and compared. The results show that the IHTC of uncoated boron steel increases with the increase of contact pressure. However, little effects on the IHTC are generated by contact pressure regarding coated boron steel. Moreover, it was also found that IHTC first increased and then decreased during martensitic transformation.

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