Abstract: Disclosed are an elastic assembly and a down lamp. The down lamp includes a lamp body and an elastic assembly. The elastic assembly includes a limiting assembly and a spring. The limiting assembly is provided with a rotating cavity. The fixing end of the spring is rotatably embedded in the rotating cavity, so that a flip angle of a movable end of the spring ranges from 0° to 90°. The present disclosure can enlarge the adjustable angle of the spring and reduce the assembly difficulty of the down lamp.

Abstract: The present disclosure provides a method for preparing heterostructure, which includes providing a donor substrate and forming a sacrificial layer on a surface of the donor substrate; forming a thin film cover layer on a surface of the sacrificial layer, wherein a top surface of the thin film cover layer is an implantation surface; performing ion implantation from the implantation surface, such that a defect layer is formed in the sacrificial layer; providing an acceptor substrate, and bonding the acceptor substrate to the implantation surface of the thin film cover layer; removing the sacrificial layer along the defect layer. The method for preparing the heterostructure of the present disclosure can successfully transfer the thin film cover layer to the acceptor substrate. The present disclosure can provide a compliant substrate, while the semiconductor donor substrate material can be reused, therefore is energy-efficient and environmental-friendly.