Abstract: Copper-tin-nickel brazing material prepared by alloys recycled from E-waste, preparation method therefor, and system thereof are provided. A preparation method for the copper-tin-nickel brazing material includes the following steps: (a) spreading nano-SiO2 on the bottom of crucible and then adding a crude copper-tin-iron-nickel alloy recycled from E-waste; (b) heating the crucible to melt the crude alloy into a metal liquid so that Zn and Pb in the metal liquid react with the SiO2 to form a slag that floats out; (c) introducing a refining gas to the bottom of metal liquid in step (b), thereby removing the scums or gases formed by Pb, Fe, S, and O in the metal liquid; (d) performing heat-preserving directional solidification on the metal liquid, to bias-aggregate the Fe and Sb at one end and remove the same to obtain a copper-based intermediate alloy; and smelting and powdering the copper-based intermediate alloy.

Abstract: The present application belongs to the field of chemical synthesis, and specifically relates to a six-membered ring-containing nucleoside compound and a preparation method thereof. The present application discloses a six-membered ring-containing nucleoside compound. The structural formula of the nucleoside compound 7 is: where R1 is selected from one of where R2 is hydroxyl or alkynyl.