Abstract: The present disclosure provides a system and method for verifying alternating current (AC)/direct current (DC) conversion of an ultralow-frequency voltage. The system includes a quantum voltage generation system, a low-frequency signal source, a follower, three switches, a double-heater-strip thermoelectric converter, a nanovoltmeter, a clock source, a high-precision digital sampling system, and an upper computer. Based on DC and AC quantum voltage technologies and with reference to the double-heater-strip thermoelectric converter, an ultralow-frequency voltage is traced to a DC quantum voltage through AC/DC conversion, and a conversion result is compared with an AC quantum voltage to verify rationality of precision and an uncertainty evaluation result of AC/DC conversion of the ultralow-frequency voltage, so as to ensure reliability of AC/DC conversion of the ultralow-frequency voltage. This resolves a problem that the AC/DC conversion result of the ultralow-frequency voltage cannot be verified.

Abstract: The present invention provides a method for manufacturing textile waste into fiber grade polyester chips applicable to textile processing. The method comprises textile waste crushing, alcoholysis, filtering and separation, cooling crystallization, pressing, decoloration, distillation purification, preheating, prepolycondensation, polycondensation, cooling strip casting, and cutting into particles. By reducing textile waste to high purity bis(2-hydroxyethyl)terephthalate (hereinafter referred to as BHET), fiber grade polyester chips applicable to textile processing are re-manufactured. Thus, efficient recycling is achieved.