First,from the constitutive relation and the transform relation connecting time domain and frequency domain,the differential equations of double negative material(DNM) are obtained.

Using the transform relation connecting time domain and frequency domain and the constitutive relation,the differential equations of double negative material(DNM) is obtained.

Analysis of scattering from double-negative metamaterials by shift operator in FDTD method;

With double-negative metamaterials constructive relation, we deduce the differential equations that describe characters of electromagnetic wave in DNG.

The underground load characters in Yinshan mine were analyzed.

This article makes an analysis on the actual wiring way of the three-phase three-wire power meter,its implementation steps and the application scope according to the phase sequence and relationship of each phase voltage and current in the actually measured phase diagram of three-phase voltage and current and the known power load character.