An apparatus for detecting materials includes a database for storing detecting spectra of detecting materials, and a tera-hertz wave applying unit for applying-tera-hertz waves having a plurality of different frequencies around a boundary between a light wave frequency and a radio wave frequency, to a predetermined position of an inspecting object. A delay line in the delay line oscillator may be implemented with either a resonant circuit or a bandpass filter of sufficient bandwidth so that the output frequency and phase noise sidebands are not attenuated. The readback signal is passed through the read channel. This device enables a digital drive scheme to be implemented. An ultrafiltration unit is used to separate the juice into clarified juice and retentate. The bearing includes a cage for holding the roller elements, wherein the cage provides an axial guiding feature for axially guiding the roller elements against at least one of the outer ring, inner ring and a separate element located outside the toroidal roller bearing.