A R\u2014Fe\u2014B base rare earth permanent magnet material consists of, in percents by weight, 25 to 45 wt % of R, 0. In one aspect of the present disclosure, security of a device may be improved by generating a working key based on a hardware secret key and at least one security parameter of the device, e. This can prevent concentration of electric current due to a short circuit between a cathode and an anode of the EL element, and can prevent failure light emission of an EL layer. The gear clutch meshes small end teeth of the gearwheel and is fitted with the teeth shaft of the middle shaft. The forces, acting individually on each wheel, aerostatically suspend the weight plus its load of the equipment or vehicle. Embodiments are applicable to systems using integrated optical light guides as the sources for imaging.