Characterization of the complete chloroplast genome of the Solanum tuberosum L. cv. Favorita (Solanaceae).

Potato (Solanum tuberosum L.), a species of the family Solanaceae, is the fourth most important food crop worldwide. Solanum tuberosum L. cv. Favorita is a long oval, smooth, yellowish-skinned potato variety with green and plump leaves. It has a dry matter content of 17.7% and starch content of 12.4-14.01% in the tuber. In order to support more genetic data for the taxonomy of S. tuberosum, the complete chloroplast (cp) genome sequence of S. tuberosum L. cv. Favorita was determined using next-generation sequencing. In leaves, the chloroplast genome accounts for 5.17% of the total genome. The entire cp genome was determined to be 155,296 bp in length. It contained large single-copy (LSC) and small single-copy (SSC) regions of 85,737 and 18,373 bp, respectively, which were separated by a pair of 25,593 bp inverted repeat (IR) regions. The genome contained 132 total genes, including 87 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The overall GC content of the genome is 37.9%. A phylogenetic tree reconstructed by 60 chloroplast genomes reveals that S. tuberosum L. cv. Favorita is most closely related to S. tuberosum L. cv. Desiree and S. tuberosum L. cv. Atlantic.

Study on the surface crystallization mechanism and inhibition method in the CMP process of aluminum alloy mirrors.

Owing to its material properties, aluminum-based optical loads are widely used in the aerospace field. At present, the main processing of an aluminum alloy mirror is single-point diamond turning followed by the combined polishing process. The surface will generate some white crystals during the chemical mechanical polishing process (CMP). These crystals can affect the improvement of surface quality and seriously reduce the processing efficiency of the whole process. In view of the above problems, four main factors of crystallization are obtained by interface theoretical analysis, Visual MINTEQ simulation of chemical morphological distribution, and experimental analysis. They are temperature, PH value of polishing fluid, solid-liquid contact angle, and impurity content of aluminum alloy. The crystallization phenomenon in the polishing process is successfully suppressed by improving the polishing process and selecting new materials. The experimental results showed that the surface roughness decreased from 7.21 to 2.98 nm without crystallization using the new method.