An electric pump may comprise a pump portion including an impeller, a motor portion configured to activate the pump portion, and a housing configured to contain the pump portion and the motor portion. The multilayer sliding member includes: a porous metal layer that is formed on a back metal; and a sliding layer that is formed by impregnating and coating the porous metal layer, wherein the sliding layer includes 1 to 25% by volume of an oxybenzoyl polyester resin, 1 to 15% by volume of a phosphate, 1 to 20% by volume of barium sulfate, and polytetrafluoroethylene resin. Four mirror-ring structures direct incoming light to a multi-spectral primary optical detector that acquires light-pattern information from which an image can be derived. The power control circuitry operates to remove an amplitude modulation component from the feedback signal using a reference amplitude signal generated from the quadrature baseband signal, thereby providing a measured gain signal of the transmit circuitry. The fastener crosses the first fastening surface and the second fastening surface infixed to each other to fasten the stem and the handlebar and is positioned within the stem and the middle portion.