Digital multimeters are electronic instruments that are used in electrical measurements. It can have many special functions, but the main function is to measure voltage, resistance and current, digital multimeter, as a modern multi-purpose electronic measuring instrument, mainly used in physical,
Lead Zinc is an important non-ferrous metals, plays an irreplaceable role in the national economy and industrial development. 80% of the world's lead and zinc are obtained by smelting lead-zinc ore. However, with the continuous mining, the easy-to-select sulfide ore resources are increasingly d
(1) Product quality standards In China's national standard for gypsum and anhydrite in cement (GB-5483-85), gypsum and anhydrite are classified into three grades according to their grades (grades are: greater than or equal to 80%, greater than or equal to 70) %, greater than or equal to 60%),