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Microalloying is an effective method to improve the comprehensive properties of copper alloys. The effects of magnesium on the microstructure, mechanical properties and anti-stress relaxation properties of CuNiSi alloys have been investigated. Results demonstrated that magnesium plays significant roles in refining the dendritic microstructure of the as-cast ingot, accelerating the precipitation decomposition, improving the mechanical properties and increasing the anti-stress relaxation properties. The incremental strength increase is due to the Orowan strengthening from the nanoscale Ni2Si and Ni3Al precipitates. As compared with the Cu–6.0Ni–1.0Si–0.5Al (wt%) alloy, the ultimate tensile strength of the designed Cu–6.0Ni–1.0Si–0.5Al–0.15Mg (wt%) alloy increases from 983.9 to 1095.7 MPa, and the electrical conductivity decreases from 27.1 to 26.6% IACS, respectively. The stress relaxation rates of the designed Cu–6.0Ni–1.0Si–0.5Al–0.15Mg alloy are 4.05% at 25 °C, 6.62% at 100 °C and 9.74% at 200 °C after having been loaded for 100 h, respectively. Magnesium significantly promotes nucleation during precipitation and maintains small precipitate size.

Since the 1980s, Sargassum fusiforme has been cultivated in Zhejiang, South China, and nowadays it becomes one of the important commercial seaweeds in China. With traditions of eating habits in the East Asian countries, this brown alga is used as food, because it contained functional oligo/polysaccharides and chemical components. and was regarded playing roles in antioxidant activities and regulating immunology. Through over 15 years’ selection, breeding and cultivation, we obtained three strains with good traits and testified their characters during the production, which included the cultivars with high yield and other two good characters, either all the selected strains were applied in the Sargassum production. To avoid confusion during the selection and nursery, it was preferred to establish one fingerprint for distinguishing the Sargassum cultivars from different strains. Random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) methods were adopted to analyze the genetic diversities of the selected S. fusiforme strains. With that, one fingerprint with RAPD markers was constructed, and one sequence characterized amplified region (SCAR) marker to S. fusiforme was obtained. It is indicated that the applied fingerprint could be valid in S. fusiforme genetic and germplasm justification, and will be positive to molecular marker assistance in its selection and cultivation.

Hizikia fusiformis is one of the important commercially cultivated seaweeds in China. Inter-simple sequence repeats (ISSR) and sequence-related amplified polymorphism (SRAP) markers were used to assess genetic structure of nine wild H. fusiformis populations collected along the coast of China. Of the 255 bands generated by 21 ISSR primers, 99.61% were polymorphic and 99.71% of 344 bands amplified by 30 SRAP primers were polymorphic. The tested high genetic diversities show that the average Nei's genetic diversity (H) were 0.1519 and 0.1624, and average Shannon's information index (I) were 0.2248 and 0.2400 in ISSR and SRAP analyses, respectively. Unweighted pair group method with arithmetic mean (UPGMA) dendrograms of the nine populations were divided into two main groups. The ISSR and SRAP analyses values of gene differentiation (G (ST), 0.5955, 0.5486, respectively) indicate that high variation exists among the nine populations, likely due to external interferences and limitation of gene flow (N (m) = 0.3397, 0.4114). Our study indicated that human activities and herbivore overgrazing had influenced the natural Hizikia populations and that the understanding of population genetics would be helpful in sustainable utilization and biomass conservation of Sargassaceae resources.