Abstract: The present disclosure belongs to the technical field of nanomaterial synthesis, and in particular, to a preparation method for a narrow-linewidth alloy quantum dot. The preparation method provided by the present disclosure includes the following steps: in a protective gas atmosphere, mixing a cadmium source, an organic ligand, and an organic solvent with a first selenium source for a nucleation reaction to obtain an organic solution of a CdSe quantum dot core; and mixing the organic solution of the CdSe quantum dot core, a zinc source and an inorganic anion source for shell coating to obtain the narrow-linewidth alloy quantum dot, where the inorganic anion source includes a second selenium source.

Abstract: Gas metal arc welding (GMAW) is a widely used process for joining metals. Its main advantage over its competition gas tungsten arc welding (GTAW) is its high productivity in depositing metals. However, to melt metal from the wire to deposit into the work-piece, additional heat is consumed and applied to the work-piece with an uncontrolled fixed proportion to the effective heat that melts the wire. Such additional heat is often in excess of the needed heat input for the work-piece. The side-effects include a waste of the energy, an increased distortion, and possible materials property degradation. This invention is to device a method to transfer this part of heat to melt the wire by adding two wires, which form a pair of arc spots, under a tungsten arc. It also devices a method to assure the arc between the two wires be maintained stable such that the transfer be successfully continuous.

Abstract: Gas metal arc welding (GMAW) is a widely used process for joining metals. Its main advantage over its competition gas tungsten arc welding (GTAW) is its high productivity in depositing metals. However, to melt metal from the wire to deposit into the work-piece, additional heat is consumed and applied to the work-piece with an uncontrolled fixed proportion to the effective heat that melts the wire. Such additional heat is often in excess of the needed heat input for the work-piece. The side-effects include a waste of the energy, an increased distortion, and possible materials property degradation. This invention is to device a method to transfer this part of heat to melt the wire by adding two wires, which form a pair of arc spots, under a tungsten arc. It also devices a method to assure the arc between the two wires be maintained stable such that the transfer be successfully continuous.