Influence of low-temperature sulfidation on the structure of ZnS thin films

ZnS thin films were prepared by sulfuring zinc thin films at different sulfuration temperatures. The crystal structure,surface morphology, defects, and optical properties of the thin films were characterized by x-ray diffraction(XRD), scanning electron microscopy(SEM), positron annihilation Doppler broadening, and UV-Vis spectrophotometer, respectively.It was found that the(200)-plane preferred orientation of the ZnS thin films changed to(111)-plane with increasing sulfidation temperature. Moreover, a number of large holes were generated at 420?C and eliminated at 440?C. The concentration of defects was lowest when the sulfuration temperature was 440?C. The optical transmission of all samples was maintained at 60%–80% in the wavelength range of 400 nm–800 nm, and the band energy of the ZnS thin films was approximately3.5 e V for all treatment temperatures except 430?C.

Cultivated hawthorn(Crataegus pinnatifida var.major)genome sheds light on the evolution of Maleae(apple tribe)

Cultivated hawthorn(Crataegus pinnatifida var.major)is an important medicinal and edible plant with a long history of use for health protection in China.Herein,we provide a de novo chromosomelevel genome sequence of the hawthorn cultivar“Qiu Jinxing.”We assembled an 823.41 Mb genome encoding 40571 genes and further anchored the779.24 Mb sequence into 17 pseudo-chromosomes,which account for 94.64%of the assembled genome.Phylogenomic analyses revealed that cultivated hawthorn diverged from other species within the Maleae(apple tribe)at approximately 35.4 Mya.Notably,genes involved in the flavonoid and triterpenoid biosynthetic pathways have been significantly amplified in the hawthorn genome.In addition,our results indicated that the Maleae share a unique ancient tetraploidization event;however,no recent independent whole-genome duplication event was specifically detected in hawthorn.The amplification of non-specific long terminal repeat retrotransposons contributed the most to the expansion of the hawthorn genome.Furthermore,we identified two paleo-sub-genomes in extant species of Maleae and found that these two sub-genomes showed different rearrangement mechanisms.We also reconstructed the ancestral chromosomes of Rosaceae and discussed two possible paleopolyploid origin patterns(autopolyploidization or allopolyploidization)of Maleae.Overall,our study provides an improved context for understanding the evolution of Maleae species,and this new highquality reference genome provides a useful resource for the horticultural improvement of hawthorn.