The present invention provides hydroxamic acid derivatives represented by the formula, having antioxidation, collagen biosynthesis promotion and skin pore contraction effects, and a method for preparation thereof. Furthermore, to reduce a residual in-phase component of the obtained differential waveform, input gain adjusting circuits adjust an input gain of the first angular velocity sensing waveform J1 and an input gain of the second angular velocity sensing waveform J2 before these waveforms J1 and J2 are entered into the differential amplification circuit. The method may also include encrypting management data associated with the input traffic data at the CSUDSU to produce encrypted management data. This first measurement may identify the current operating point of the sensor. Thus, by using the keys distributed between the main channel and the sub-channels, a correlation can be given between the key operations and the channels’ hierarchical construction to thereby facilitate the changing and selection of the main channels and the sub-channels in the hierarchical construction in digitalanalog broadcasts.