Abstract: The present disclosure provides a method and system for creating dipole moment model. The method is applied to a tested circuit and includes: performing a near-field measurement on the tested circuit, to obtain a near-field electric field and a near-field magnetic field related to the tested circuit; performing a two-dimensional divergence calculation on the near-field electric field and the near-field magnetic field, to obtain a near-field electric divergence field and a near-field magnetic divergence field; performing a convolution calculation on the near-field electric divergence field and the near-field magnetic divergence field with a digital filter; and building a dipole moment matrix equivalent to the tested circuit according to a result of the convolution calculation.

Abstract: A belt sander includes a main casing, a frame arm rotatably connected to the main casing, an abrasive belt mounted to the frame arm and adapted to be driven by electric power, a positioning member, a first sensor and a second sensor. The positioning member is movably mounted to the main casing and is movable relative to the main casing between a releasing position, where the first and second sensors are in a first sensor state, and where the second sensor generates a first signal for ceasing the electric power, and a first engaging position, where the first and second sensors are in the second sensor state, and where the second sensor generates a second signal for conducting the electric power.