Papers by Author: Xi Ying Ma

Abstract: The paper presents the fabrication of Si₃N₄ nanowires prepared on Si substrate by plasma-enhanced chemical vapor deposition (PECVD) technology. The nanowires were formed using silane (SiH₄) and nitrogen (N₂) as reactive gases under the action of Fe catalysts. They are characteristics of superlong straight and flexural types observed by field emission scanning electron microscopy (FESEM). The former with a length of 3.96 mm has smooth surface and uniform diameter resulting from an orientation growth process, while the latter is 5.20 mm formed by two nanowires twisted together with a squeezing growth way. A growth model has been developed for the formation of the nanowires, and the growth mechanism of the nanowires has been discussed. The straight and flexural Si₃N₄ nanowires can be used as nano-scaled bridge, spring, and cantilever in the fabrication of nano-machine systems.

Abstract: The beautiful luster of freshwater pearls is closely related to its multiplayer microstructure. We present the improvement of their luster by refinement their superficial microstructure of pearls by rare earth cerium (REE) inducing grown. The pearls were cultured in freshwater containing 0 (control group), 0.5, and 1 mg·L^-1 REE Ce additive, respectively. As the concentration of Ce in the aqueous increasing, we find that their superficial microstructure take large change. The shape of the blocks that builds up the microstructure changes from anomalous to round discs, and finally to perfect regular square sheets. Correspondingly, the glossiness of the pearls changed with the microstructure, in which the pearls with the regular hexagonal blocks having the highest glossiness.