Fig. 1. Working principle of full-bridge inverter circuits. (a) The first stage of the full-bridge inverter circuit (T₁ and T₄ are on, current flows; T₂ and T₃ are off, no current flows; current flows to the right on load R); (b) the second stage of the full-bridge inverter circuit (T₁ and T₄ are off, no current flows; T₂ and T₃ are on, current flows; current flows to the left on load R); (c) pulse signals controlling G₁‒G₄ and the output voltage on the load

Fig. 2. Magnetic focusing device and in vivo and in vitro magnetic focusing experiments^[7]. (a) Magnetic focusing device (signal generator produces current, which is amplified by an amplifier and fed into the coil through a matching circuit) and in vitro magnetic focusing experiment; (b) in vivo experiment at the tail of a mouse

Fig. 3. Ferrite coil^[13]. (a) Ferrite coil schematic; (b) magnetic induction intensity simulation of ferrite coil

Fig. 4. Helmholtz-like coil^[16]. (a) Helmholtz-like coil photo; (b) a research platform jointly built by magnetic hyperthermia equipment and spectrometer