The old theory of how insect repellents work was that DEET blocks the insect's ability to detect lactic acid from people, which acts as a mosquito magnet.

The oil-line structure, control system and their working principles of the hydraulic lifting system for the main magnets of CYCIAE-30 cyclotron are introduced.

Based on electromagnetic theory, electromagnet is used for actuator of active suspension and a general electromagnetic actuator is constructed.